Synthesis and preliminary biological evaluation of new antiproliferative aromatic analogues of 1α,25-dihydroxyvitamin D3

European Journal of Medicinal Chemistry 86 (2014) 381e393

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European Journal of Medicinal Chemistry journal homepage: http://www.elsevier.com/locate/ejmech

Original article

Synthesis and preliminary biological evaluation of new antiproliferative aromatic analogues of 1a,25-dihydroxyvitamin D3 Emmanuel Thomas, Jean-Daniel Brion, Jean-François Peyrat* ^tenay-Malabry Laboratoire de Chimie Th
erapeutique, BioCIS-CNRS (UMR 8076), Universit
e Paris-Sud, Facult
e de Pharmacie, Rue J.B. Cl
ement, 92296 Cha Cedex, France

a r t i c l e i n f o

a b s t r a c t

Article history: Received 12 March 2014 Received in revised form 10 July 2014 Accepted 10 July 2014 Available online 15 July 2014

In an effort to develop novel vitamin D3 analogues, a series of aromatic compounds was synthetized, using efficient Negishi cross coupling between alkenylzinc reagents of the C,D-ring moiety of vitamin D3, and various substituted aromatic halides as A-ring mimics. The study aimed at exploring the influence of the replacement of the original vitamin D3 diene by a styrene unit on the biological activities. Potency in the induction of the differentiation of HL-60 cells for the lead compound 36 was 12 fold less important than calcitriol correlating with a weaker binding affinity for VDR. © 2014 Elsevier Masson SAS. All rights reserved.

Keywords: Aromatic analogues of vitamin D3 Negishi coupling reaction Antiproliferative activity

1. Introduction The hormonally active metabolite of vitamin D3, the 1a,25dihydroxyvitamin D3 or calcitriol [1,25(OH)2D3, 1], was known to control calcium homeostasis and bone metabolism [1]. Complementary to its classical role, calcitriol was found to display antiproliferative and prodifferentiation activity [2e4]. In addition to these biological activity, calcitriol was found to be involved in apoptosis, angiogenesis and immunomodulation control [5]. Most of these activities are expressed via a binding to the ubiquitous receptor VDR [6] present in numerous tissues including skin, brain, heart, pancreas, kidney, intestine, colon [7e11], prostate [12], ovary and breast [7,13]. Currently, calcitriol and analogues might be potential drugs for the treatment of tumors such as leukemia, breast and prostate cancers [14e17], and, in vivo models, can potentiate the activity of clinically anticancer agents such as cisplatin [18] or paclitaxel [19]. However, when targeting cancers, the development of these molecules in a therapeutic approach is severely limited by the potent calcemic effects [20,21]. One of the strategy chosen to overcome hypercalcemic limitation is the structural modification of calcitriol. Until recently, most of developed 1a, 25-(OH)2-D3 analogues were modified at their * Corresponding author. E-mail address: [email protected] (J.-F. Peyrat). http://dx.doi.org/10.1016/j.ejmech.2014.07.037 0223-5234/© 2014 Elsevier Masson SAS. All rights reserved.

side chain in 17b position, which has a fundamental role in VDRbinding and metabolism [22e25]. Thereafter, the X ray crystallographic studies of a complex of the natural hormone 1 and a mutant vitamin D receptor revealed that modifications on the A-ring are allowed [26]. Thus, several groups focused on this task to increase the binding affinity for VDR [27,28]. From these studies, relatively few examples of analogues having modifications at the central dienic part were reported. So far, the most interesting compound described is the stilbene 2. This compound displays VDR agonist activities which were only 10 fold less potent than that of 1 and induced only low calcemic effects [29]. In support of an ongoing medicinal chemistry program directed toward vitamin D3 analogues, it was of interest to synthesize compounds 3 in which the original diene was blocked in an aromatic nucleus and linked to a C,D ring unit. As the hydroxyl group in C1 position of calcitriol proved to be essential for biological activity, polyhydroxylated chains on the aromatic nucleus, as a mimic of the original A-ring, were retained in compounds 3. In this structural moiety, at least one of two hydroxyl groups is at the same distance (6 carbon atoms in bold Fig. 1) of the CD-rings than that of the hydroxyl group in C1 position in 1. The assumption was that the introduction of rigidity in the structure, compare to the natural conformational flexibility of vitamin D3 and analogues, would lead to potent inductors of differentiation with low calcemic effects.

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2.1.2. Obtention of the CD-rings parts The synthesis of the C,D-ring parts is shown in Schemes 2 and 3. The vinyl bromide 4 and 5 (ratio E:Z ¼ 97:3) were prepared respectively from vitamin D3 according to the Toh/Okamura protocol [31] and Trost procedure (Scheme 2) [32]. In regard to active alkyne analogues already described in the literature, CD-ring moiety bearing an alkynyl function in the side chain was selected (Scheme 3) [33]. Thus, the synthesis of the CD-ring indane 12a and 12b was performed following Castedo protocol [34] from the InhoffenLythgoe diol [35]. Selective tosylation of this latter [36] followed by protection of the secondary alcohol offered ethers 7a [37] and 7b [38]. Substitution of the tosyl group by lithium derivatives of 8a or 8b, led to alkynes 9 (9a: 82%, 9b: 91%) which were deprotected to afford the corresponding alcohols 10 (10a: 67%, 10b: 94%). Oxidation using PDC, to avoid the cleavage of the THP group of 10b, or PCC [36] offered the corresponding ketones 11a and 11b. The desired E-bromoolefins 12a and 12b were finally obtained in good overall yield through Wittig bromomethylenation [32]. Fig. 1. Vitamin D3 and targeted analogues 3.

2. Results and discussion 2.1. Chemistry 2.1.1. General retrosynthesis of targeted analogues The general pathway for the synthesis of analogues 3 follows a convergent strategy based on an efficient Negishi coupling reactions between the organozinc derivatives [30] (A, Scheme 1) and aryl halides (B, Scheme 1).

Scheme 1. Synthetic approaches.

2.1.3. Obtention of the A-ring parts Once the CD-rings parts in our hands, the material required for the Negishi coupling was the phenylhalides part. In our aim to determine new structure-relationships in this series of analogues, we decided to synthesize different A-ring portions, 1-(4phenylhalides)propane-1,3-diol 13 and bishydroxymethylphenyl halides 14 and 15 (Scheme 4). The A-ring derivatives 13 were synthesized from two commercially available products: 1,3-dibromobenzene and 3hydroxypropane nitrile (Scheme 5). The condensation of the monolithian species of dibromobenzene, at 40  C, with the silyl ether 16, offered the ketone 17 in good yield. This latter undergoes a carbonyl reduction using NaBH4 and the resulting secondary alcohol 18 was subsequently protected to provide the bis-silyl ether 19. The corresponding iodide compound 13a was obtained in a 79% yield after classical halogen metal exchange reaction [39]. Ketone 17 was used in parallel to synthesized acetonide iodide compound 13c. Reduction and deprotection of 17 led to the diol 20 [40] which was protected as acetonide and subjected to halogen metal exchange to offer 13c in 49% overall yields across the three steps. The O-bis(hydroxymethyl)phenyls 14 were obtained from commercial 4-bromophtalic acid, after reduction in presence of BH3$THF leading to diol 21 [41], protection as silyl ether (14a [41])

Scheme 2. Obtention of the CD-rings parts 4 and 5. a) i) KMnO4, H2O/EtOH, 10  C to 40  C, 63%; ii) Pb(OAc)4, pyridine, CH2Cl2, 0  C, 82%; b) i) RuCl3 (0.15 equiv.), NaIO4 (3.6 equiv.), CCl4/CH3CN/H2O, r.t., 49%; c) TES-OTf, 2,6-lutidine, CH2Cl2, 78  C to r.t., 84%; d) NaHMDS (4.8 equiv.), [BrCH2(PPh3)]þBr (5 equiv.)., THF, 60  C to r.t., 51%.

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383

Scheme 3. Obtention of the CD-rings parts 12. a) DHP, PTSA 1 mol.%, CH2Cl2, 0  C to r.t., 7a, 84% or TES-OTf, 2,6-lutidine, 10  C to r.t., 7b, 98%; b) n-BuLi, 8a, dioxane, 5  C to r.t. then reflux 40 h, 82%; c) n-BuLi, 8b, dioxane, 5  C to r.t. then reflux 40 h, 91%; d) amberlyst 15, MeOH, 50  C, 12 h, 67%; e) PCC, CH2Cl2, r.t. 90%; f) TBAF, THF, r.t., 94%; g) PDC, CH2Cl2, r.t., 86%; h) NaHMDS, [BrCH2(PPh3)]þBr, THF, 60  C to r.t., 53% (for 12a and 12b).

followed by halogen/metal exchange provided the compound 14b in 69% overall yield (Scheme 6). The triflate of the A-ring moiety 15 was envisaged to explore the pseudo-halogen reactivity [42]. The synthetic pathway started from commercial 3-hydroxyphthalic anhydride (Scheme 6) which was reduced in phenol 22 with LiAlH4. Compound 22 was then transformed into the allylic ether 23. Further diol protection and allyl group removing [43], led to intermediate phenol 25 which was converted to the corresponding desired triflate 15 in 78% overall yield. ~ o have reported that functionalized vinyl iodides reacted Mourin efficiently with organozinc C,D fragments, in the presence of tetrakis(triphenylphosphine)palladium [30,44]. Thus, this catalyst was chosen for the study of the Negishi cross-coupling reaction. The organozinc derivatives was first prepared in situ by treatment of vinyl bromides with t-BuLi, and trapping the resulting anion with ZnBr2 (Scheme 7). The resulting vinylzinc bromide was then coupled with aryl halides in the presence of a catalytic amount of Pd(PPh4)3 (5 mol.%). The results are summarized in Table 1. First attempt was performed using vinyl bromide 4 and aryl bromide 19. Surprisingly, no reaction occurred and 19 was totally recovered. Note that all attempts at cross coupling failed, using diethyl ether or THF as solvent at room temperature or at 60  C. To our delight, room temperature reaction of more reactive aryl iodides in the presence of Pd(PPh3)4 [45], 13c and 14b, gave the expected coupling products (26aec, 27aeb, 28 and 29) in good yields. Results showed that the presence of three sterically hindered silyl ether groups on the two coupling partners results in a drastic decrease of yield (26b and 27a) even if activating the coupling at higher temperature (70  C). This assumption was verified with the replacement of the bis-silylated part 14a by 12b bearing an acetonide group (products 26c and 27b) which offer the desired coupling product in good yield.

2.1.4. Negishi cross coupling The coupling result between aryl bromide 19 and 4 in head, the reactivity of 4-methoxyphenyl trifluoromethanesulfonate was evaluated during the Negishi reaction in the same conditions.

Scheme 4. A-ring mimic parts.

The desired coupling product was isolated in 83% yield. However, the coupling of triflate compound 15 with 4, produced a very low yield. Optimization of the reaction conditions showed that, in this case, a temperature of 70  C and an additive (LiCl (3 equiv.)) were required [46,47]. In these conditions, compound 30 and 31 were obtained, from 15 and 4 in 52% and from 12b and 15 in 55% yield respectively (Table 1). Note that, in our hands, tetrakis triphenylphosphine palladium was always the best catalysis. The use of Pd(dba)2/tri(2-furyl)phosphine [48,49] or Pd(dba)2/(1.1)-bisdiphenyl)phosphino ferrocene [50,51], led to drastic decrease of yield, even with A-ring 15, while such palladium species were known to be effective with triflates. In a final step, all protected compounds were next subjected to TBAF or DOWEX resin treatment in MeOH at 60  C and to a purification by high-performance chromatography (HPLC) to offer final compounds 32e38 in 76e96% yields (Scheme 8).

2.2. Biology: binding affinity to VDR and induction of HL-60 cell differentiation In vitro tests were performed on with ovarian Sf9 cells line where the human recombinant VDR are over expressed, following the Ross protocol [52]. The VDR affinities and potencies of induction of HL-60 cell differentiation of the novel synthesized analogues are summarized in Table 2 in comparison with those of the natural hormone 1. All new synthesized compounds showed a lower binding affinity for the VDR compare to calcitriol, despite the presence of hydroxyl groups on the ring A mimic at the same distance (6 carbon atoms) from rings C,D than that existing in the parent compound 1. The introduction of rigidity in the central diene system of the molecules reduced the affinity for the VDR. However, 3,4bis(hydroxymethyl)analogue 33 and 36 showed the better affinity for VDR. Thus, the ability of these new analogues to induce differentiation of HL-60 cell [53] was tested and results are summarized in Table 2. The established HL-60 cellular differentiation activity of the tested compounds is 2000 to 12 fold weaker in comparison with the hormone 1. However, compound 36 showed the best results, with a differentiation activity 12 fold lower than that of calcitriol 1. The influence of the alkynyl side chain is again brought to the fore when comparing compounds 35 and 36 [a sentence has been deleted]. The compound 36 provides new insight into the structure-relationships of vitamine D3 analogues. A strained central diene can exist in a compound which displayed a significant affinity for the VDR and a moderate HL-60 cell differentiation activity.

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Scheme 5. Synthesis of A-ring mimic 13. a) i) n-BuLi, Et2O, 40  C, 70%; ii) 16, Et2O, 40  C, then HCl 0.5 M, 70%; b) NaBH4, THF/MeOH (1/1), 0  C, 91%; c) TBDMSCl, Imidazole, DMAP cat., CH2Cl2, r.t., 90%. d) i) n-BuLi, THF, 78  C; ii) I2, THF, r.t., (13a ¼ 79% and 13c ¼ 87%); e) i) NaBH4, THF/MeOH (1/1), 0  C; ii) HCl 3 M, 89% for the two steps; f) 2,2dimethoxypropane, CH2Cl2, amberlyst 15, 63%.

3. Conclusion In conclusion, we have described the synthesis, using Negishi coupling reaction as a key step, and the biological evaluation of original 1a,25(OH)2D3 analogues bearing a mimic of the ring A presents in the parent compound 1. To investigate structureeactivity relationships, different substitutions on the ring A mimics and on the side chain of the C,D rings part were envisaged. In this way, an efficient synthetic route to the novel compounds library has been developed. VDR binding affinity and HL-60 cell differentiation revealed that compound 36 exhibited an interesting profile despite a lower activity than calcitriol (1). However, initial in vitro biological evaluation is not sufficient to conclude about the impact of the rigidity of the central diene on the biological activities. The expected antitumoral activities and low calcemic effect of analogues will be evaluated and reported separately. 4. Experimental

(mp) were recorded on a Büchi B-450 apparatus and were uncorrected. NMR spectra were performed on a Bruker AMX 200 (1H, 200 MHz; 13C, 50 MHz), Bruker AVANCE 300 or Bruker AVANCE 400 (1H, 400 MHz; 13C, 100 MHz). Unless otherwise stated, CDCl3 was used as solvent. Chemical shifts d are in ppm, and the following abbreviations are used: singlet (s), doublet (d), triplet (t), multiplet (m), quintet (q), broad doublet (bd), broad multiplet (bm), broad triplet (bt) and broad singlet (bs). Elemental analyses (C, H, N) were performed at the microanalyses Service of the Faculty of Pharmacy ^tenay-Malabry (France) with a Perkin Elmer 2400 CHNS inat Cha strument and were within 0.4% of the theorical values otherwise stated. IR spectra were performed with a Bruker type Vector 22. ESI Mass spectra were obtained using an LC Bruker Esquire electrospray ionization instrument. ESI-TOF IR spectra were obtained using an LCT Micromass (Waters) and IE mass spectra on Polaris Thermoquest (Funnigan). High-performance liquid chromatography (HPLC) c was performed on a Merck LabChrom (C-18 column Merck lichrospher RP18 (124*4)). Optical rotations were measured using a Perkin Elmer 241 MC.

4.1. Chemistry All glasswares were oven-dried at 140  C. Tetrahydrofuran (THF) was distilled from sodium-benzophenone ketyl. Melting points

Scheme 6. Synthesis of A-ring mimics 14 and 15. a) BH3$THF, THF, 0  C to 40  C, 85%; b) TBDMSCl, Imidazole, DMAP cat., CH2Cl2, r.t., 98%; c) i) n-BuLi, THF, 78  C; ii) I2, THF, r.t., 83%. d) LiAlH4, THF, 78  C to reflux, 86%; e) allyl bromide, K2CO3, KI 10%, acetone, 60  C, 71%; f) TBDMSCl, Imidazole, DMAP cat., CH2Cl2, r.t., 92%; g) NaBH4, Pd(PPh3)4 5%, THF/MeOH (1/4), 0  C, 95%, h) Tf2O, Pyridine, CH2Cl2, 0  C, 89%.

4.1.1. Compound 6 To a solution of Inhoffen-Lythgoe diol (1.95 g, 9.18 mmol, 1 equiv.) in fresh distillated pyridine (39 mL) at 0  C, was added ptoluenesulfonyl chloride (2.6 g, 13.8 mmol). The mixture was stored a night at 4  C and hydrolyzed with ice. The mixture was extracted with Et2O. The organic layer was washed with a solution of HCl 1 M (until pH 1), and with a saturated solution of sodium dicarbonate, dried over Na2SO4, and evaporated. The crystals were then placed in a dessicator for a night and give compound 6 (3.3 g, 9.18 mmol, 99%, white crystals).

Scheme 7. Negishi coupling conditions.

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Table 1 Negishi cross coupling of A and CD-rings. A-ring

CD-ring

Coupling product

Yield (%)

0

19

4

26a

82

13a

4

26a

31a

13a

5

26b

61

13c

5

26c

33a

13a

12a

27a

67

13c

12b

27b

91

14b

4

28

91

14B

12B

29

52b

15

4

30

55b

15 a b

Same yield at 70  C. 3 eq. of LiCl and 70  C.

12b

31

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Scheme 8. Coupling products and corresponding deprotected final compounds 32e38. a) TBAF, THF, r.t., 48 h; b) Dowex 50WN2-200, MeOH 95%, 60  C, 2 h.

Rf ¼ 0.21 (cyclohexane/AcOEt: 75/25). m.p. (AcOEt) ¼ 110  C (Litt. 109e110  C). IR (film, cm1): n 3344, 2931, 2880, 2864, 1697, 1457, 1360, 1067, 1034, 987, 941, 629. 1H RMN (400 MHz, CDCl3): d 4.05 (1H, bs), 3.6 (1H, dd, 3J ¼ 10.5 Hz, 3J ¼ 3.2 Hz), 3.33 (1H, dd, 3 J ¼ 10.5 Hz, 3J ¼ 6.6 Hz), 2.02e1.07 (13H, m), 1.01 (3H, d, 3 J ¼ 6.6 Hz), 0.93 (3H, s). 13C RMN (100 MHz, CDCl3): d 69.1, 67.6, 52.9, 52.3, 41.7, 40.1, 38.1, 33.4, 26.5, 22.5, 17.3, 16.5, 13.4. MS (ESIþ) m/z: 213.1 ((MþH)þ, 100), 193.1 (30), 177.2 (100), 135.1 (28). 4.1.2. Compound 9a To a solution of alkyne 8a (2.64 g, 13.3 mmol, 4 equiv.) in dry dioxane (40 mL) at 5  C, was added BuLi (5.32 mL, 13.3 mmol, 4 equiv.). The mixture was stirred for 30 min at 5  C, then 1 h at r.t. A solution of 7a (1.5 g, 3.3 mmol, 1 equiv.) in dioxane (7 mL) was then added dropwise, and the mixture was heated to reflux. After 40 h, the mixture was poured into a mixture of NaHCO3 in Ice. The mixture was extracted with AcOEt, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 95/5) to give compound 9a [1.3 g, 2.9 mmol, 82%, brown oil]. Rf ¼ 0.7 (cyclohexane/AcOEt: 8/2). IR (film, cm1): n 2929, 2855, 1462, 1376, 1248, 1200, 1023, 1001, 835, 775. 1H RMN (400 MHz,

Table 2 VDR binding properties and HL-60 differentiating activities of vitamin D3 analogues. Compound

% Inhibition of control specific binding to VDRa

HL-60 cell differentiation IC50 (mM)b

1 32 33 34 35 36 37 38

100 13 23 9 12 74 30 21

0.05 ± 5.4 ± 1.4 ± 7.8 ± 63.2 ± 0.6 ± 32.4 ± >100

0.04 0.12 0.42 4.82 5.40 0.04 8.17

a Competitive binding of 1a,25-(OH)2D3 (1) and the synthesized vitamin D analogues to the human recombinant vitamin D receptor. b Induction of differentiation of HL-60 promyelocytes to monocytes by 1a,25(OH)2D3 and the synthesized analogues.

CDCl3): d 4.69 (1H, bs), 4.54 (1H, bs), 3.33 (2H, m), 2.12 (1H, m), 2.04 (1H, m), 2.12e0.95 (12H, m), 1.27 (6H, s), 0.91 (3H, d, 3J ¼ 6.5 Hz), 0.77 (3H, s), 0.70 (9H, s), 0.01 (6H, s). 13C RMN (100 MHz, CDCl3): d 94.2, 86.6, 81.3, 76.8, 66.2, 62.3, 55.6, 52.1, 42.0, 40.4, 35.1, 33.2, 33.1, 32.4, 32.3, 26.5, 25.7, 25.6, 23.8, 22.4, 18.9, 17.7, 17.3, 17.1, 13.3, 3.2. MS (ESIþ) m/z: 499.4 ((MþNa)þ, 100). 4.1.3. Compound 9b To a solution of alkyne 8b (2.8 g, 16.8 mmol, 4 equiv.) in dry dioxane (50 mL) at 5  C, was added BuLi (6.65 mL, 16.6 mmol, 4 equiv.). The mixture was stirred for 30 min at 5  C, then 1 h at r.t. A solution of 7b (2 g, 4.4 mmol, 1 equiv.) in dioxane (10 mL) was then added dropwise, and the mixture was heated to reflux. After 40 h, the mixture was poured into a mixture of NaHCO3 in ice. The mixture was extracted with AcOEt, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 95/5) to give compound 9b [1.9 g, 4 mmol, 91%, colorless oil]. Rf ¼ 0.5 (cyclohexane/AcOEt: 95/5). 1H RMN (400 MHz, CDCl3): d 5.13 (1H, bs), 4.10 (1H, bs), 3.86 (1H, m), 3.43 (1H, m), 2.46 (3H, s), 2.22 (1H, dd, 3J ¼ 4.3 Hz, 2J ¼ 15.6 Hz), 2.09 (1H, m), 1.97 (1H, m), 1.82 (2H, m), 1.72 (1H, m), 1.65e1.30 (11H, m), 1.58 (1H, m), 1.48 (6H, s), 1.07 (3H, d, 3J ¼ 6.7 Hz), 0.96 (9H, t, 3J ¼ 6.7 Hz), 0.94 (3H, s), 0.59 (6H, q, 3J ¼ 8.1 Hz). 13C RMN (100 MHz, CDCl3): d 96.2, 84.6, 83.5, 71.8, 70.3, 62.8, 56.5, 53.9, 42.8, 41.5, 35.8, 35.3, 32.7, 31.6, 30.6, 27.7, 26.4, 26.2, 23.8, 20.8, 19.5, 18.4, 14.3, 7.3, 5.6. MS (ESIþ) m/z: 499.4 ((MþNa)þ, 100). 4.1.4. Compound 10a To a solution of 9a (1.1 g, 2.3 mmol, 1 equiv.) in dry MeOH (20 mL), was added Amberlyst 15® (1 g). The mixture was heated at 50  C for 1 h, filtered over a pad of silica, washed with MeOH and concentrated in vacuo. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 93/7) to give compound 10a [734 mg, 1.5 mmol, 67%, colorless oil]. Rf ¼ 0.2 (cyclohexane/AcOEt: 95/5). IR (film, cm1): n 3420, 2981, 2856, 1472, 1376, 1246, 1159, 1036, 835, 775. 1H RMN (400 MHz, CDCl3): d 4.08 (1H, bs), 2.22 (1H, dd, 3J ¼ 3.5 Hz, 2J ¼ 16.5 Hz), 2.02

E. Thomas et al. / European Journal of Medicinal Chemistry 86 (2014) 381e393

(1H, dd, 3J ¼ 7.5 Hz, 2J ¼ 16.6 Hz), 1.98 (2H, m), 1.71e1.13 (10H, m), 1.56 (1H, m), 1.43 (6H, s), 1.04 (3H, d, 3J ¼ 6.6 Hz), 0.94 (3H, s), 0.85 (9H, s), 0.0 (6H, s). 13C RMN (100 MHz, CDCl3): d 86.9, 81.3, 69.3, 66.4, 55.5, 52.6, 41.8, 40.2, 35.0, 33.6, 33.4, 33.3, 27.0, 25.7, 25.5, 22.5, 19.0, 17.4, 17.2, 13.6, 4.1. MS (EIþ, 70 eV) m/z: 392 (2), 335 (80), 259 (25), 201 (58), 163 (33), 81 (100), 73 (100), 55 (96).

4.1.5. Compound 10b To a solution of silyl ether 9b (1.8 g, 3.8 mmol, 1 equiv.) in dry THF (30 mL) were added molecular sieves 4 Å, and a solution of tetrabutyl ammonium fluoride (7.55 mL, 7.55 mmol, 2 equiv.). The mixture was stirred for a night at r.t. After hydrolysis, the mixture was extracted with AcOEt, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The crude residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 9/1) to give compound 10b [1.3 g, 3.61 mmol, 94%, colorless oil]. IR (film, cm1): n 3471, 2982, 2926, 2851, 2660, 1613, 1568, 1360, 1109, 1022, 885, 685. 1H RMN (400 MHz, CDCl3): d 5.06 (1H, bs), 3.94 (1H, bs), 3.80 (1H, m), 3.37 (1H, m), 2.22 (1H, dd, 3J ¼ 4.1 Hz, 2 J ¼ 15.6 Hz), 1.91e1.23 (19H, m), 1.53 (1H, m), 1.47 (6H, s), 1.07 (3H, d, 3J ¼ 6.5 Hz), 0.94 (3H, s). 13C RMN (100 MHz, CDCl3): d 96.3, 84.6, 83.5, 71.9, 68.7, 62.9, 56.5, 53.9, 42.6, 41.6, 35.8, 34.9, 32.7, 31.6, 30.6, 27.7, 26.3, 26.2, 23.4, 20.8, 19.5, 18.4, 14.2. MS (ESIþ) m/z: 385.3 ((MþNa)þ, 100).

4.1.6. Compound 11a To a suspension of pyridinium chlorochromate (576 mg, 2.67 mmol, 3 equiv.) in dry CH2Cl2 (16 mL), was added dropwise a solution of alcohol 10a (350 mg, 0.89 mmol, 1 equiv.) in CH2Cl2 (4 mL). The mixture was stirred for 4 h at r.t., filtered over a pad of silica, washed with CH2Cl2, and concentrated in vacuo. The residue was purified by flash chromatography on silica gel (cyclohexane/ AcOEt: 95/5) to give compound 11a [312 mg, 0.8 mmol, 90%, colorless oil].  Rf ¼ 0.33 (cyclohexane/AcOEt: 95/5). [a]25 D þ23.5 (c 0.21, CHCl3). IR (film, cm1): n 2956, 2930, 2856, 1716, 1462, 1245, 1159, 1036, 834, 775. 1H RMN (400 MHz, CDCl3): d 2.54 (1H, dd, 3J ¼ 7.8 Hz, 2 J ¼ 7.6 Hz), 2.29 (2H, m), 2.13 (3H, m), 2.05e1.55 (8H, m), 1.65 (1H, m), 1.45 (6H, s), 1.13 (3H, d, 3J ¼ 6.3 Hz), 0.87 (3H, s), 0.85 (9H, s), 0.10 (6H, s). 13C RMN (100 MHz, CDCl3): d 209.7, 87.4, 81.8, 67.1, 62.0, 56.0, 49.9, 41.1, 39.4, 35.8, 33.7, 27.9, 26.2, 26.1, 24.3, 19.7, 19.6, 17.4, 12.7, 0.0. MS (ESIþ) m/z: 413.3 ((MþNa)þ, 100).

4.1.7. Compound 12a To a suspension of (bromomethyl)triphenylphosphonium bromide (5.12 g, 11 mmol, 5 equiv.) in dry THF (9 mL) at 60  C, was added dropwise a solution of NaHMDS in THF (1.84 mL, 3.68 mmol, 4.8 equiv.). The reaction mixture was stirred for 1 h, and a yellow color was observed. A solution of ketone 11a (300 mg, 0.77 mmol, 4.8 equiv.) in THF (1.5 mL) was added dropwise. After 2 h of stirring, the mixture became brown and cyclohexane was then added. The mixture was filtered over a pad of silica (elution with cyclohexane) and solvents were dried in vacuo. The crude residue was purified by flash chromatography (cyclohexane) to give the compound 12a [190 mg, 0.41 mmol, 53%, colorless oil]. Rf ¼ 0.75 (cyclohexane). 1H RMN (400 MHz, CD3COCD3): d 5.45 (1H, bs), 2.65 (1H, dd, 3J ¼ 7.2 Hz, 2J ¼ 7.4 Hz, H7), 2.05e1.1 (14H, m), 1.25 (6H, s, H), 0.89 (3H, d, 3J ¼ 6.7 Hz), 0.68 (9H, s), 0.41 (3H, s), 0.0 (6H, s). 13C RMN (100 MHz, CD3COCD3): d 144.8, 97.1, 86.5, 81.1, 66.2, 55.5, 54.4, 45.1, 39.4, 35.4, 32.8, 30.6, 27.0, 25.2, 25.1, 22.2, 21.6, 18.7, 18.4, 11.7, 3.6. MS (ESIþ) m/z: 490.3 ((MþNa)þ, 100). Anal. Calcd for [C25H43BrOSi]: C, 64.21, H, 9.27. Found: C, 64.08, H 9.12.

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4.1.8. Compound 11b
q.) in dry To a solution of alcohol 10b (1.3 g, 3.59 mmol, 1 e CH2Cl2 (45 mL) was added pyridinium dichromate (3.76 g, 10 mmol, 3 equiv.). The mixture was stirred for 4 h and was filtered over a pad of silica (elution with EtOAc). After concentration in vacuo, the residue was purified by flash chromatography (Cyclohexane/AcOEt: 8/2) to give the ketone 11b [1.1 g; 3 mmol, 86%, colorless oil].  Rf ¼ 0.59 (cyclohexane/AcOEt: 8/2). [a]25 D 43.7 (c 0.17, CHCl3). 1 H RMN (400 MHz, CDCl3): d 5.29 (1H, bs), 4.03 (1H, m), 3.59 (1H, m), 2.72 (1H, dd, 3J ¼ 6 Hz, 2J ¼ 5.6 Hz), 2.2e1.2 (19H, m), 1.63 (3H, s), 1.58 (3H, s), 1.54 (1H, m), 1.26 (3H, d, 3J ¼ 5.8 Hz), 0.89 (3H, s). 13C RMN (100 MHz, CDCl3): d 211.4, 95.9, 84.0, 82.2, 71.3, 63.2, 61.7, 55.4, 49.5, 40.7, 38.7, 34.9, 31.9, 31.6, 30.9, 27.1, 25.6, 25.3, 23.8, 20.5, 18.9, 18.8, 12.5. MS (ESIþ) m/z: 406.2 ((Mþ2Na)þ, 100), 383.2 ((MþNa)þ, 5). 4.1.9. Compound 12b To a suspension of (bromomethyl)triphenylphosphonium bromide (6.65 g, 15.2 mmol, 5 equiv.) in dry THF (33 mL) at 60  C, was added dropwise a solution of NaHMDS in THF (7.32 mL, 14.6 mmol, 4.8 equiv.). The reaction mixture was stirred for 1 h, and a yellow color was observed. A solution of ketone 11b (1.1 g, 3.05 mmol, 1 equiv.) in THF (6.5 mL) was added dropwise. After 2 h of stirring, the mixture became brown and cyclohexane was then added. The mixture was filtered over a pad of silica (elution with cyclohexane) and solvents were dried in vacuo. The crude residue was purified by flash chromatography (cyclohexane/AcOEt: 98/2) to give the compound 12b [726 mg, 1.66 mmol, 53%, colorless oil]. Rf ¼ 0.46 (cyclohexane/AcOEt: 95/5). 1H RMN (400 MHz, CD3COCD3): d 5.62 (1H, bs); 5.01 (1H, bs), 3.75 (1H, m), 3.34 (1H, m), 2.72 (1H, m), 2.1e1.2 (20H, m), 1.35 (3H, s), 1.29 (3H, s), 0.97 (3H, d, 3 J ¼ 6.2 Hz), 0.48 (3H, s). 13C RMN (100 MHz, CD3COCD3): d 144.8, 97.2, 95.2, 83.9, 82.3, 70.8, 61.9, 55.6, 54.4, 45.2, 39.5, 35.3, 31.7, 30.7, 30.6, 29.7, 26.9, 25.4, 25.2, 22.2, 21.7, 19.8, 18.6, 11.7. MS (ESIþ) m/z: 460 ((MþNa)þ, 100). Anal. Calcd for [C24H37BrO2]: C, 65.89, H, 8.57. Found: C, 65.81, H 8.48. 4.1.10. Compound 17 To a solution of 1.3-dibromobenzene (5 g, 212 mmol, 2 equiv.) in dry Et2O (30 mL) at 78  C, was added dropwise a solution of nBuLi 1.6 M in Et2O (13.5 mL, 216 mmol, 2.04 equiv.). The mixture was allowed to 45  C and stirred 15 min.. A solution of nitrile 16 (1.96 g, 106 mmol, 1 equiv.) in dry Et2O (10 mL) was then added dropwise at 40  C. The mixture was stirred at this temperature for 1 h. Then the mixture was allowed to come to r.t. After hydrolysis, the mixture was extracted with AcOEt, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography (cyclohexane/AcOEt: 98/2) to give the compound 17 [2.55 g, 7.43 mmol, 70%, yellow oil]. Rf ¼ 0.46 (cyclohexane/AcOEt: 98/2). IR (film, cm1): n 2954, 2929, 2856, 1687. RMN (400 MHz, CDCl3): d 8.15 (1H, t, 4J ¼ 1.7 Hz, H5), 7.85 (1H, dt, 3J ¼ 7.7 Hz, 4J ¼ 1.7 Hz), 7.75 (1H, dt, 3J ¼ 7.7 Hz, 4 J ¼ 1.5 Hz), 7.25 (1H, dd, 3J ¼ 7.7 Hz, 3J ¼ 1.7 Hz), 4.00 (2H, t, 3 J ¼ 6.4 Hz), 3.11 (2H, t, 3J ¼ 6.4 Hz), 0.80 (9H, s), 0.00 (6H, s). 13C RMN (100 MHz, CDCl3): d 197.8, 139,1, 135.7, 131.2, 130.0, 126.6, 122.8, 59.1, 41.6, 25.7, 18.1, 0.0. MS (ESIþ) m/z: 365 ((MþNa)þ, 100), 208 (85). 4.1.11. Compound 18 To a solution of ketone 17 (1.2 g, 3.5 mmol) in 25 mL of a solution of THF/MeOH (1/1, v/v) at 0  C, was added NaBH4 (530 mg, 13.5 mmol, 2.04 equiv.). The mixture was stirred during 12 h at r.t. After hydrolysis, the aqueous phase was extracted with Et2O. The organic phase was washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash

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chromatography (cyclohexane/AcOEt: 9/1) to give the compound 18 [1.08 g, 3.1 mmol, 91%, colorless oil]. Rf ¼ 0.33 (cyclohexane/AcOEt: 9/1). IR (film, cm1): n 3417, 2953, 2928, 2883, 2857, 1471, 1427. RMN (400 MHz, CDCl3): d 7.43 (1H, t, 4 J ¼ 1.3 Hz), 7.29 (1H, dt, 3J ¼ 7.6 Hz, 4J ¼ 1.7 Hz), 7.18 (1H, dt, 3 J ¼ 7.1 Hz, 4J ¼ 1.4 Hz), 7.10 (1H, dd, 3J ¼ 7.6 Hz, 3J ¼ 7.1 Hz), 4.82 (1H, t, 3J ¼ 6.2 Hz), 3.75 (2H, t, 3J ¼ 6.4 Hz), 1.82 (2H, t, 3J ¼ 6.3 Hz), 0.81 (9H, s), 0.00 (6H, s). 13C RMN (100 MHz, CDCl3): d 146.8, 130.1, 129.7, 128.7, 124.2, 122.4, 73.4, 61.9, 4.3, 25.7 (X3), 18.0, 0.0. MS (ESIþ) m/z: 346 ((MþH)þ, 100). 4.1.12. Compound 19 To a solution of alcohol 18 (630 mg, 1.83 mmol, 1 equiv.), in presence of a catalytic amount of DMAP (20 mg), in dry CH2Cl2 at r.t., was added tert-butyldimethylsilyl chloride (551 mg, 3.66 mmol, 2 equiv.). The mixture was stirred for a night at r.t. After hydrolysis, the mixture was extracted with CH2Cl2, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography (cyclohexane/AcOEt: 8/2) to give the compound 19 [755 mg, 1.65 mmol, 90%, colorless oil]. Rf ¼ 0.23 (cyclohexane). IR (film, cm1): n 2954, 2929, 2857, 1254. 1H RMN (400 MHz, CDCl3): d 7.42 (1H, m), 7.30 (1H, dt, 3 J7e8 ¼ 7.4 Hz, 4J ¼ 2.1 Hz), 7.20 (1H, m), 7.10 (1H, t, 3J ¼ 7.4 Hz), 4.75 (1H, dd, 3J ¼ 5.9 Hz, 3J ¼ 7.8 Hz), 3.75e3.40 (2H, m), 1.91e1.63 (2H, m), 0.85 (9H, s), 0.80 (9H, s), 0.00 (12H, s). 13C RMN (100 MHz, CDCl3): d 148.0, 129.8, 129.5, 128.9, 124.3, 122.1, 70.9, 59.1, 43.8, 25.8, 25.7, 18.1, 4.7. MS (EI, 70 eV), m/z: 459 ([M]þ., 88), 443 (36), 205(35), 163 (35), 149 (100), 73 (46). 4.1.13. Compound 13a To a solution of aryl bromide 19 (700 mg, 1.52 mmol, 1 equiv.) in dry THF (10 mL), at 78  C, was added dropwise a solution of n-BuLi
q.). The yellow mixture was stirred (1.1 mL, 1.82 mmol, 1.2 e 30 min and a solution of iodide (967 mg, 3.8 mmol, 2.5 equiv.) in dry THF (6 mL) was added dropwise. The reaction mixture was stirred for 2 h at 78  C and for a night at r.t. After hydrolysis by addition of a saturated solution of Na2S2O3, the aqueous phase was extracted with AcOEt. The organic layer was washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography (cyclohexane/CH2Cl2: 95/51) to give the compound 13a [585 mg, 1.15 mmol, 76%, pale yellow oil]. Rf ¼ 0.42 (cyclohexane/CH2Cl2: 90/10). IR (film, cm1): n 2953, 2928, 2885, 2857, 1471, 1253, 1089. 1H RMN (400 MHz, CDCl3): d 7.62 (1H, t, 4J ¼ 1.2 Hz), 7.52 (1H, dt, 3J ¼ 7.7 Hz, 4J ¼ 1.2 Hz), 7.21 (1H, dm, 3J ¼ 7.7 Hz), 6.99 (1H, t, 3J ¼ 7.7 Hz), 4.75 (1H, dd, 3 J ¼ 5.77 Hz, 3J ¼ 7.5 Hz), 3.76e3.41 (2H, m), 1.95e1.63 (2H, m), 0.87 (9H, s), 0.83 (9H, s), 0.00 (6H, s), 0.02 (3H, s), 0.18 (3H, s). 13C RMN (100 MHz, CDCl3): d 148.0, 135.8, 134.9, 129.7, 124.9, 93.9, 70.8, 59.1, 43.8, 25.8, 25.7, 18.1, 4.7. MS (ESIþ) m/z: 529 ((MþNa)þ, 100), 483 (18), 259 (40), 213 (5). 4.1.14. Compound 13b To a solution of diol 20 (1.2 g, 5.2 mmol, 1 equiv.) in dry CH2Cl2 were added Amberlyst 15® (150 mg) and dimethoxypropane (1.28 mL; 10 mmol; 2 equiv.). The reaction mixture was stirred for a night at r.t., filtered over a pad of silica and solvent was remove by evaporation in vacuo. The residue was purified by flash chromatography (cyclohexane/AcOEt: 9/1) to give the compound 13b [907 mg, 3.3 mmol, 63%, translucent oil]. Rf ¼ 0.17 (cyclohexane/AcOEt: 9/1). IR (film, cm1): n 3064, 2991, 2953, 2869, 2717, 2017, 1596, 1570, 1476, 1424, 1377, 1196, 1161, 1099, 969, 844, 781, 696. 1H RMN (400 MHz, CD3COCD3): d 7.71 (1H, t, 4J ¼ 1.8 Hz), 7.63 (1H, dt, 3J ¼ 7.6 Hz, 4J ¼ 1.8 Hz), 7.34 (1H, dm, 3 J ¼ 7.6 Hz), 7.31 (1H, t, 3J ¼ 7.6 Hz), 5.22 (1H, dd, 3J ¼ 3.6 Hz, 3 J ¼ 11.2 Hz), 4.32 (1H, m), 4.03 (1H, m), 1.91 (2H, m), 1.73 (3H, s),

1.55 (3H, s). 13C RMN (100 MHz, CD3COCD3): d 145.8, 129.9, 129.8, 128.4, 124.4, 121.7, 96.2, 69.9, 59.3, 33.3, 29.6, 18.5. 4.1.15. Compound 13c To a solution of aryl bromide 13b (680 mg, 2.42 mmol, 1 equiv.) in dry THF (13 mL), at 78  C, was added dropwise a solution of nBuLi (1.18 mL, 2.95 mmol, 1.2 equiv.). The yellow mixture was stirred 30 min and a solution of iodide (1.55 g, 6.12 mmol, 2.5 equiv.) in dry THF (5 mL) was added dropwise. The reaction mixture was stirred for 2 h at 78  C and for a night at r.t. After hydrolysis by addition of a saturated solution of Na2S2O3 the aqueous phase was extracted with AcOEt. The organic layer was washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography (cyclohexane/AcOEt: 9/1) to give the compound 13c [680 mg, 2.14 mmol, 87%, pale yellow oil]. Rf ¼ 0.35 (cyclohexane/AcOEt: 9/1). IR (film, cm1): n 2990, 2952, 2867, 1566, 1376, 1196, 1161, 1105, 969, 780, 694. 1H RMN (400 MHz, CDCl3): d 7.73 (1H, t, 4J ¼ 1.6 Hz), 7.60 (1H, dt, 3J ¼ 7.7 Hz, 4 J ¼ 1.6 Hz), 7.34 (1H, dm, 3J ¼ 7.7 Hz), 7.07 (1H, t, 3J ¼ 7.8 Hz), 4.86 (1H, dd, 3J ¼ 3.1 Hz, 3J ¼ 11.5 Hz), 4.07 (2H, m), 1.76 (2H, m), 1.55 (3H, s), 1.49 (3H, s). 13C RMN (100 MHz, CDCl3): d 145.8, 136.1, 134.5, 130.1, 125.0, 98.3, 96.8, 69.6, 59.4, 33.4, 29.6, 18.6. MS (ESIþ) m/z: 341 ((MþNa)þ, 100), 319 ((MþH)þ, 53). 4.1.16. Compound 14b To a solution of aryl bromide 14a (2.4 g, 5.4 mmol, 1 equiv.) in dry THF (27 mL), at 78  C, was added dropwise a solution of nBuLi (2.58 mL, 6.43 mmol, 1.2 equiv.). The reaction mixture was stirred 30 min and a solution of iodide (3.4 g, 13.5 mmol, 2.5 equiv.) in dry THF (11 mL) was added dropwise. The reaction mixture was stirred for 2 h at 78  C and for a night at r.t. After hydrolysis by addition of a saturated solution of Na2S2O3, the aqueous phase was extracted with AcOEt. The organic layer was washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography (cyclohexane/AcOEt: 98/2) to give the compound 14b [2.2 mg, 0.83 mmol, 83%, yellow solid]. Rf ¼ 0.7 (cyclohexane/AcOEt: 95/5). M.p. ¼ 36e37  C. IR (film, cm1): n 2954, 2929, 2885, 2856, 1471, 1254, 1130, 1068, 833, 814, 774. 1H RMN (400 MHz, CD3COCD3): d 7.84 (1H, bs), 7.64 (1H, dd, 3 J ¼ 8.1 Hz, 4J ¼ 1.8 Hz), 7.24 (1H, d, 3J ¼ 8.1 Hz), 4.81 (2H, s), 4.77 (2H, s), 0.97 (9H, s), 0.95 (9H, s), 0.14 (6H, s), 0.12 (6H, s). 13C RMN (100 MHz, CD3COCD3): d 140.9, 138.0, 135.6, 135.0, 128.5, 91.8, 61.8, 61.5, 25.3, 17.8, 4.1. MS (ESIþ) m/z: 515.1 ((MþNa)þ, 100), 388.1 (41). 4.1.17. Compound 15 To a solution of phenol 25 (400 mg, 1.05 mmol, 1 equiv.) in dry CH2Cl2 at 0  C, were added dropwise pyridine (835 mL, 10.5 mmol, 10 equiv.) triflic anhydride (195 mL, 1.15 mmol, 1.1 equiv.). The mixture was stirred for 2 h at 0  C, 1 h at t.a. and was hydrolyzed with a saturated solution of ammonium chloride. The mixture was extracted with AcOEt, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 97/3) to give compound 15 [480 mg, 0.93 mmol, 89%, colorless oil]. Rf ¼ 0.86 (cyclohexane/AcOEt: 95/5). IR (film, cm1): n 2955, 2931, 2858, 1461, 1423, 1252, 1212, 1141, 1067, 915, 833, 775. 1H RMN (400 MHz, CD3COCD3): d 7.72 (1H, d, 3J ¼ 7.8 Hz), 7.54 (1H, t, 3 J ¼ 7.8 Hz), 7.31 (1H, d, 3J ¼ 7.8 Hz), 5.04 (2H, s), 4.88 (2H, s), 0.98 (9H, s), 0.92 (9H, s), 0.15 (12H, s). 13C RMN (100 MHz, CD3COCD3): d 147.3, 145.4, 130.5, 127.5, 122.6, 120.5, 62.4, 56.8, 26.3, 26.1, 17.9, 5.4, 5.2. 19F RMN (CD3COCD3): d 104.4. MS (ESIþ) m/z: 537.2 ((MþNa)þ, 100).

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4.1.18. Compound 22 To a suspension of LiAlH4 (1.85 g, 0.049 mmol, 4 equiv.) in dry THF (70 mL) at 78  C, was added dropwise, a solution of 4Hydroxisoben-zofuran-1,3-dione (2 g, 12 mmol, 1 equiv.) in dry THF (18 mL). The reaction mixture was stirred 1 h at 78  C, 2 h at r.t., and a night under reflux and was hydrolyzed with HCl 1 M). The mixture was stirred for a night at r.t. After hydrolysis, the mixture was extracted with AcOEt, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The solid was recrystallized in AcOEt to give the compound 22 [1.6 g, 0.01 mmol, 86%, white crystals]. Rf ¼ 0.31 (cyclohexane/CH2Cl2: 9/1). m.p. (AcOEt) ¼ 82e84  C. IR (film, cm1): n 3535, 3261, 3082, 2937, 2886, 1588, 1467, 1277, 1165, 980, 961, 786. 1H RMN (400 MHz, CD3COCD3): d 8.65 (1H, bs), 7.07 (1H, t, 3J ¼ 7.8 Hz), 6.85 (1H, dd, 3J ¼ 6.5 Hz, 4J ¼ 1.1 Hz), 6.78 (1H, dd, 3 J ¼ 8.1 Hz, 4J ¼ 1.1 Hz), 4.88 (2H, s), 4.64 (2H, s). 13C RMN (100 MHz, CD3COCD3): d 153.8, 141.2, 127.9, 123.3, 119.7, 115.1, 62.5, 56.8. MS (ESIþ) m/z: 177.1 ((MþNa)þ, 100). 4.1.19. Compound 23 To a solution of phenol 22 (800 mg, 5.19 mmol, 1 equiv.) in acetone (50 mL) were added K2CO3 (1.43 g, 10.4 mmol, 2 equiv.), and KI (86 mg, 0.5 mmol, 0.1 equiv.). The reaction mixture was
q.) was heated to reflux and allyl bromide (545 mL, 6.2 mmol, 1.2 e added dropwise. The reaction mixture was stirred for 3 h at 60  C and was hydrolyzed. The mixture was extracted with EtO2, washed with a solution of saturated NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 2/8) to give compound 23 [715 mg, 3.68 mmol, 71%, white crystals]. Rf ¼ 0.37 (cyclohexane/AcOEt: 2/8). m.p. (AcOEt) ¼ 100e102  C. IR (film, cm1): n 3274, 3010, 2928, 2871, 1581, 1459, 1423, 1267, 1256, 1075, 993, 781, 733, 660. 1H RMN (400 MHz, CD3COCD3): d 7.04 (1H, t, 3J ¼ 8.2 Hz), 6.75 (1H, dd, 3J ¼ 8.2 Hz, 4J ¼ 1.1 Hz), 6.68 (1H, dd, 3J ¼ 8.2 Hz, 4J ¼ 1.1 Hz), 5.89 (1H, m), 5.21 (1H, dq, 3 J ¼ 17.3 Hz, 4J ¼ 1.5 Hz, 2J ¼ 1.6 Hz), 5.10 (1H, dq, 3J ¼ 10.5 Hz, 4 J ¼ 1.5 Hz, 2J ¼ 1.6 Hz), 4.62 (2H, s), 4.46 (2H, s), 4.37 (2H, dt, 3 J ¼ 5.1 Hz, 4J ¼ 1.5 Hz). 13C RMN (100 MHz, CD3COCD3): d 152.2, 141.2, 133.1, 128.9, 128.3, 121.9, 117.4, 112.2, 69.3, 63.7, 56.0. MS (ESIþ) m/z: 217.1 ((MþNa)þ, 100). 4.1.20. Compound 24 To a solution of diol 23 (400 mg, 2.1 mmol, 1 equiv.) in dry CH2Cl2 (10 mL) were added imidazole (1.1 g, 16.8 mmol, 8 equiv.), DMAP (30 mg, 0.2 mmol, 0.1 equiv.) and tert-butyldimethylsilyl chloride (1.24 g, 8.4 mmol 4 equiv.). The reaction mixture was stirred at r.t. for 24 h and was hydrolyzed. The mixture was extracted with CH2Cl2, washed with H2O, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 95/5) to give the compound 24 [800 mg, 1.89 mmol, 92%, colorless oil]. Rf ¼ 0.73 (cyclohexane/AcOEt: 9/1). IR (film, cm1): n 2954, 2929, 2857, 1588, 1471, 1253, 1055, 1005, 832, 773. 1H RMN (400 MHz, CD3COCD3): d 7.05 (1H, t, 3J ¼ 8.1 Hz), 6.79 (1H, dd, 3 J ¼ 8.1 Hz, 4J6e4 ¼ 1.0 Hz), 6.72 (1H, dd, 3J ¼ 8.1 Hz, 4J ¼ 1.0 Hz), 5.93 (1H, m), 5.29 (1H, dq, 3J ¼ 17.0 Hz, 4J ¼ 1.8 Hz, 2J ¼ 1.4 Hz), 5.05 (1H, dq, 3J ¼ 10.5 Hz, 4J ¼ 1.8 Hz, 2J ¼ 1.4 Hz), 4.78 (2H, s), 4.68 (2H, s), 4.39 (2H, dt, 3J ¼ 5.1 Hz, 4J ¼ 1.8 Hz), 1.21 (9H, s), 0.93 (9H, s), 0.10 (6H, s), 0.08 (6H, s). 13C RMN (100 MHz, CD3COCD3): d 154.8, 139.7, 133.8, 128,2, 124.7, 118.8, 116.1, 110.8, 68.9, 62.1, 55.2, 25.3, 17.9, 3.8. MS (ESIþ) m/z: 445.2 ((MþNa)þ, 100). 4.1.21. Compound 26a To a suspension of vinyl bromide 4 (304 mg, 0.89 mmol, 1.5 equiv.) in dry THF (9 mL) at 78  C, was added dropwise a

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solution of t-BuLi in pentane (1.45 mL, 2.2 mmol, 3.7 equiv.). The mixture was stirred for 15 min and 6 mL of a solution of zinc dibromide in dry THF (294 mg, 1.31 mmol, 2.2 equiv.) were added dropwise. The mixture is then stirred for 1 h 30 min at 10  C. In a second flask, a solution of 14a (300 mg, 0.59 mmol, 1 equiv.) and tetrakis (triphenylphosphine) palladium (34 mg, 0.03 mmol, 0.05 equiv.) in 6 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with CH2Cl2, washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/CH2Cl2: 95/5) to give the compound 26a [310 mg, 0.48 mmol, 82%, colorless oil]. Rf ¼ 0.28 (cyclohexane/CH2Cl2: 95/5). IR (film, cm1): n 2953, 2929, 2858, 2360, 2343, 1971, 1715, 1605, 1464, 1438, 1257, 1087, 1027, 837, 724, 264. 1H RMN (400 MHz, CD3COCD3): d 7.24 (1H, t, 3 J ¼ 7.7 Hz), 7.14 (1H, m), 7.11 (1H, d, 3J ¼ 7.7 Hz), 7.06 (1H, d, 3 J ¼ 7.7 Hz), 6.07 (1H, s), 4.82 (1H, dd, 3J ¼ 4.7 Hz, 3J ¼ 7.9 Hz), 3.73 (1H, m), 3.58 (1H, m), 2.89 (1H, dd, 3J ¼ 6.7 Hz, 3J ¼ 7 Hz), 2.10 (1H, m), 2.05 (1H, m), 1.78 (2H, m), 1.74 (1H, m), 1.53 (1H, m), 1.68e1.51 (4H, m), 1.41 (2H, m), 1.35 (1H, m), 1.34 (1H, m), 1.33 (2H, m), 1.16 (2H, m), 1.15 (2H, m), 1.04 (1H, m), 0.96 (3H, d, 3J ¼ 6.2 Hz), 0.92e0.88 (6H, d, 3J ¼ 6.5 Hz), 0.92e0.88 (18H, s), 0.65 (3H, s), 0.04 (12H, s). 13C RMN (100 MHz, CD3COCD3): d 145.2, 142.7, 138.1, 127.53, 127.4, 126.4, 123.2, 120.8, 71.7, 59.5, 56.6, 56.1, 45.7, 43.9, 40.5, 39.4, 36.1, 36.0, 29.5, 27.9, 27.6, 25.8, 25.7, 23.8, 23.5, 22.7, 22.4, 22.3, 18.8, 18.1, 11.9, 4.7. MS (ESIþ) m/z: 663 ((MþNa)þ, 5), 557 (13), 507 (96), 377 (90), 279 (100). 4.1.22. Compound 26c To a suspension of vinyl bromide 5 (120 mg, 0.25 mmol, 1 equiv.) in dry THF (3 mL) at 78  C, was added dropwise a solution of tBuLi in pentane (315 mL, 0.53 mmol, 2.1 equiv.). The mixture was stirred for 15 min and 1.5 mL of a solution of zinc dibromide in dry THF (86 mg, 0.38 mmol, 2.1 equiv.) was added dropwise. The mixture is then stirred for 1 h 30 at 10  C. In a second flask, a solution of 13c (121 mg, 0.38 mmol, 1.5 equiv.) and tetrakis (triphenylphosphine) palladium (29 mg, 0.025 mmol, 0.1 equiv.) in 2 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with CH2Cl2, washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 98/2) to give the compound 26c [89 mg, 0.15 mmol, 61%, colorless oil]. Rf ¼ 0.52 (cyclohexane/AcOEt: 9/1). 1H RMN (400 MHz, CD3COCD3): d 7.14 (1H, t, 3J ¼ 7.4 Hz), 7.10 (1H, s), 7.04 (1H, d, 3 J ¼ 7.4 Hz), 6.97 (1H, d, 3J ¼ 7.4 Hz), 5.97 (1H, s), 4.82 (1H, dd, 3 J ¼ 3.2 Hz, 3J ¼ 8.1 Hz), 4.0 (1H, m), 3.7 (1H, m), 2.8 (1H, d, 3 J ¼ 14.0 Hz), 2.0e1.0 (19H, m), 1.51 (1H, m), 1.39 (3H, s), 1.25 (3H, s), 1.10 (6H, s), 0.87 (3H, d, 3J ¼ 6.2 Hz), 0.85 (9H, t, 3J ¼ 7.3 Hz), 0.55 (3H, s), 0.49 (6H, q, 3J ¼ 7.3 Hz). 13C RMN (100 MHz, CD3COCD3): d 142.9, 142.4, 138.2, 127.6, 127.5, 126.2, 123.7, 120.8, 98.1, 73.2, 70.7, 59.5, 56.5, 55.9, 45.5, 45.3, 40.3, 36.3, 35.9, 33.5, 29.7, 29.5, 29.2, 27.5, 27.4, 23.3, 22.1, 20.5, 18.5, 18.3, 11.4, 6.5. MS (ESIþ) m/z: 605.4 ((MþNa)þ, 100), 563.4 (37). 4.1.23. Compound 27b To a suspension of vinyl bromide 12b (300 mg, 0.69 mmol, 1 equiv.) in dry THF (6 mL) at 78  C, was added dropwise a solution of t-BuLi in pentane (84 mL, 1.44 mmol, 2.1 equiv.). The mixture was stirred for 15 min and 5 mL of a solution of zinc dibromide in dry THF (232 mg, 1.03 mmol, 1.5 equiv.) were added

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dropwise. The mixture is then stirred for 1 h 30 min at 10  C. In a second flask, a solution of 13c (327 mg, 1.03 mmol, 1.5 equiv.) and tetrakis (triphenylphosphine) palladium (79 mg, 0.069 mmol, 0.1 equiv.) in 5 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with CH2Cl2, washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 95/5) to give the compound 27b [253 mg, 0.46 mmol, 67%, colorless oil]. Rf ¼ 0.36 (cyclohexane/AcOEt:9/1). IR (film, cm1): n 2991, 2953, 2869, 2245, 1566, 1377, 1196, 1161, 1095, 969, 854, 731, 694. 1H RMN (400 MHz, CDCl3): d 7.27 (1H, t, 3J ¼ 7.5 Hz), 7.19 (1H, s), 7.17 (1H, d, 3 J ¼ 7.5 Hz), 7.11 (1H, d, 3J ¼ 7.5 Hz), 6.06 (1H, s), 5.08 (1H, bs), 4.89 (1H, dd, 3J ¼ 2.4 Hz, 3J ¼ 11.6 Hz), 4.1 (1H, m), 3.95 (2H, m), 3.49 (1H, m), 2.89 (1H, d, 3J ¼ 12,9 Hz), 2.20e1.40 (21H, m), 1.62 (1H, m), 1.56 (3H, s), 1.51 (3H, s), 1.48 (6H, s), 1.09 (3H, d, 3J ¼ 5.4 Hz), 0.64 (3H, s). 13 C RMN (100 MHz, CDCl3): d 142.6, 142.1, 138.5, 128.0, 127.9, 126.4, 123.3, 120.8, 98.6, 96.1, 83.8, 82.8, 71.6, 71.3, 63.3, 60.0, 56.0, 55.5, 45.6, 40.3, 35.7, 33.4, 32.0, 30.9, 30.1, 29.9, 29.4, 27.3, 25.7, 25.3, 23.4, 22.2, 20.6, 19.1 (x2), 12.0. 4.1.24. Compound 28 To a suspension of vinyl bromide 4 (250 mg, 0.73 mmol, 1.5 equiv.) in dry THF (7 mL) at 78  C, was added dropwise a solution of t-BuLi in pentane (1.2 mL, 1.8 mmol, 3.7 equiv.). The mixture was stirred for 15 min and 5 mL of a solution of zinc dibromide in dry THF (242 mg, 1.07 mmol, 2.2 equiv.) were added dropwise. The mixture is then stirred for 1 h 30 min at 10  C. In a second flask, a solution of 14b (240 mg, 0.49 mmol, 1 equiv.) and tetrakis (triphenylphosphine) palladium (56 mg, 0.048 mmol, 0.05 equiv.) in 5 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with CH2Cl2, washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/CH2Cl2: 9/1) to give the compound 28 [280 mg, 0.45 mmol, 91%, colorless oil]. Rf ¼ 0.31 (cyclohexane/CH2Cl2: 9/1). IR (film, cm1): n 2952, 2928, 2856, 1653, 1463, 1377, 1253, 1159, 1066, 834, 814, 774. 1H RMN (400 MHz, CDCl3): d 7.35 (1H, d, 3J ¼ 7.9 Hz), 7.30 (1H, s), 7.10 (1H, d, 3J ¼ 7.9 Hz), 5.98 (1H, s), 4.67 (2H, s), 4.64 (2H, s), 2.93 (1H, m), 2.15e1.0 (18H, m), 1.41 (1H, m), 0.96 (18H, s), 0.94 (3H, d, 3 J ¼ 6.0 Hz), 0.89 (6H, d, 3J ¼ 6.2 Hz), 0.66 (3H, s), 0.10 (12H, s). 13C RMN (100 MHz, CDCl3): d 142.7, 137.9, 137.4, 136.4, 127.4, 127.2, 126.5, 120.8, 62.9, 62.8, 56.8, 56.3, 45.9, 40.6, 39.5, 36.2, 36.1, 29.5, 28.0, 27.7, 25.9, 23.6, 23.2, 22.8, 22.6, 22.4, 19.2, 18.9, 11.9, 5.2. MS (ESIþ) m/z: 650.2 ((MþNa)þ, 100), 535.1 (27). 4.1.25. Compound 29 To a suspension of vinyl bromide 12b (300 mg, 0.69 mmol, 1.5 equiv.) in dry THF (7 mL) at 78  C, was added dropwise a solution of t-BuLi in pentane (1.13 mL, 1.69 mmol, 3.7 equiv.). The mixture was stirred for 15 min and 5 mL of a solution of zinc dibromide in dry THF (226 mg, 1 mmol, 2.2 equiv.) were added dropwise. The mixture is then stirred for 1 h 30 min at 10  C. In a second flask, a solution of 14b (225 mg, 0.46 mmol, 1 equiv.) and tetrakis (triphenylphosphine) palladium (53 mg, 0.046 mmol, 0.1 equiv.) in 5 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with CH2Cl2, washed with a saturated solution of NaCl, dried over Na2SO4, and

evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 95/5) to give the compound 29 [300 mg, 0.41 mmol, 91%, translucent oil]. Rf ¼ 0.65 (cyclohexane/AcOEt: 95/5). IR (film, cm1): n 2930, 2856, 1651, 1462, 1378, 1361, 1253, 1125, 1074, 986, 835, 775. 1H RMN (400 MHz, CD3COCD3): d 7.37 (1H, d, 3J ¼ 8.1 Hz), 7.35 (1H, s), 7.09 (1H, d, 3J ¼ 8.1 Hz), 6.10 (1H, s), 5.16 (1H, m), 4.83 (2H, s), 4.80 (2H, s), 3.88 (1H, m), 3.45 (1H, m), 2.96 (1H, m), 2.17 (1H, m), 2.2e1.2 (12H, m), 2.06 (1H, m), 1.76 (1H, m), 1.67 (1H, m), 1.64 (1H, m), 1.56 (1H, m), 1.51 (1H, m), 1.43 (6H, s), 1.40 (1H, m), 1.12 (3H, d, 3 J ¼ 6.3 Hz), 0.94 (18H, s), 0.68 (3H, s), 0.11 (12H, s). 13C RMN (100 MHz, CD3COCD3): d 143.1, 139.1, 138.1, 136.7, 128.1, 127.9, 127.5, 121.8, 96.3, 84.8, 83.5, 71.9, 63.4, 62.9, 56.9, 56.3, 46.5, 41.2, 36.5, 32.8, 30.7, 30.6, 29.1, 28.1, 26.4, 26.3, 24.4, 24.4, 23.1, 19.6, 18.9 (x2), 17.9, 12.5, 4.3. MS (ESIþ) m/z: 745.6 ((MþNa)þ, 5), 381.3 (100). 4.1.26. Compound 30 To a suspension of vinyl bromide 4 (220 mg, 0.65 mmol, 1.5 equiv.) in dry THF (6 mL) at 78  C, was added dropwise a solution of t-BuLi in pentane (1.06 mL, 1.59 mmol, 3.7 equiv.). The mixture was stirred for 15 min and 4.5 mL of a solution of zinc dibromide in dry THF (213 mg, 0.95 mmol, 2.2 equiv.) were added dropwise. The mixture is then stirred for 1 h 30 min at 10  C. In a second flask, a solution of 15a (222 mg, 0.43 mmol, 1 equiv.) and tetrakis (triphenylphosphine) palladium (25 mg, 0.02 mmol, 0.05 equiv.) in 4.5 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with CH2Cl2, washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/CH2Cl2: 95/5) to give the compound 30 [140 mg, 0.22 mmol, 52%, colorless oil]. Rf ¼ 0.31 (cyclohexane/CH2Cl2: 95/5). IR (film, cm1): n 2952, 2928, 2856, 1463, 1377, 1253, 1126, 1066, 834, 774. 1H RMN (400 MHz, CDCl3): d 7.56 (1H, d, 3J ¼ 7.7 Hz), 7.37 (1H, t, 3J ¼ 7.7 Hz), 7.14 (1H, d, 3J ¼ 7.7 Hz), 6.09 (1H, s), 4.58 (2H, s), 4.31 (2H, s), 2.41 (1H, m), 2.12e1.02 (19H, m), 0.82 (9H, s), 0.77 (9H, s), 0.76 (3H, d, 3 J ¼ 5.8 Hz), 0.73 (6H, d, 3J ¼ 6.6 Hz), 0.44 (3H, s), 0.01 (6H, s), 0.00 (6H, s). 13C RMN (100 MHz, CDCl3): d 142.3, 138.7, 138.4, 136.4, 130.4, 128.3, 127.5, 118.9, 63.8, 59.6, 56.9, 55.8, 46.2, 40.7, 39.3, 36.3, 36.1, 29.9, 27.2, 26.6, 25.8, 23.3, 23.6, 22.9, 22.5, 21.8, 18.6, 18.3, 12.2, 4.8. MS (ESIþ) m/z: 649.6 ((MþNa)þ, 100). 4.1.27. Compound 31 To a suspension of vinyl bromide 12b (330 mg, 0.75 mmol, 1.5 equiv.) in dry THF (8 mL) at 78  C, was added dropwise a solution of t-BuLi in pentane (1.23 mL, 1.85 mmol, 3.7 equiv.). The mixture was stirred for 15 min and 5 mL of a solution of zinc dibromide in dry THF (248 mg, 0.95 mmol, 2.2 equiv.) were added dropwise. The mixture is then stirred for 1 h 30 min at 10  C. In a second flask, a solution of 15 (257 mg, 0.5 mmol, 1 equiv.) and tetrakis (triphenylphosphine) palladium (58 mg, 0.05 mmol, 0.1 equiv.) in 5 mL of dry THF was stirred for 15 min and was added to the mixture at 78  C. The mixture was then stirred for a night at r.t. and was hydrolyzed by addition of a saturated solution of ammonium chloride. The mixture was extracted with AcOEt, washed with a saturated solution of NaCl, dried over Na2SO4, and evaporated. The residue was purified by flash chromatography on silica gel (cyclohexane/AcOEt: 95/5) to give the compound 31 [199 mg, 0.27 mmol, 55%, colorless oil]. Rf ¼ 0.39 (cyclohexane/AcOEt: 95/5). 1H RMN (400 MHz, CD3COCD3): d 7.55 (1H, d, 3J ¼ 7.8 Hz), 7.41 (1H, t, 3J ¼ 7.8 Hz), 7.19 (1H, d, 3J ¼ 7.8 Hz), 6.11 (1H, s), 5.01 (1H, m), 4.61 (2H, s), 4.33 (2H, s), 3.75 (1H, m), 3.31 (1H, m), 2.18 (1H, m), 2.2e1.2 (18H, m), 2.07

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(1H, m), 1.62 (1H, m), 1.34 (6H, s), 1.01 (3H, d, 3J ¼ 6.2 Hz), 0.84 (9H, s), 0.78 (9H, s), 0.47 (3H, s), 0.02 (12H, s). 13C RMN (100 MHz, CD3COCD3): 142.3, 138.5, 136.6, 134.8, 130.7, 129.3, 127.9, 121.4, 97.4, 85.2, 84.5, 72.9, 63.9 (x2), 61.9, 57.1, 56.6, 46.7, 41.9, 37.5, 33.8, 32.7, 31.7, 29.1, 27.4, 27.2, 25.6, 23.9, 22.6, 21.9, 20.1, 18, 17.6, 13.3, 2.8. MS (ESIþ) m/z: 745.5 ((MþNa)þ, 100), 630.4 (63), 515.3 (25). 4.1.28. Compound 32 To a solution of disilylether 26a (310 mg, 0.48 mmol, 1 equiv.) in dry THF (20 mL) was added a solution of TBAF in THF (5.81 mL, 5.81 mmol, 12 equiv.). The yellow and translucent reaction mixture was stirred at room temperature for 24 h. A saturated solution of sodium bicarbonate was added (20 mL). The aqueous phase was extracted with AcOEt (x4). The combined organic phase was dried, filtered, and concentrated in vacuo. The residue was purified by a flash chromatography (Cyclohexane/AcOEt: 6/4) and HPLC (column deltapack® C18, CH3CN/H2O 85/15) to give the compound 32 [192 mg, 0.46 mmol, 96%, colorless oil].  Rf ¼ 0.2 (cyclohexane/AcOEt: 1/1). [a]25 D ¼ þ68 (both enantiomers, c 0.11, CHCl3). IR (film, cm1): n 3368, 2951, 2932, 2869, 1704, 1602, 1466, 1376, 1240, 1048, 707, 649. 1H RMN (400 MHz, CDCl3): d 7.25 (1H, t, 3J ¼ 7.6 Hz), 7.14 (1H, s), 7.11 (1H, d, 3J7e6 ¼ 7.6 Hz), 7.06 (1H, d, 3J5e6 ¼ 7.6 Hz), 6.05 (1H, s), 4.88 (1H, dd, 3J ¼ 3.2 Hz, 3 J ¼ 8.4 Hz), 3.81 (2H, t, 3J ¼ 4.7 Hz), 2.88 (1H, d, 3J ¼ 12.5 Hz), 2.11 (1H, m), 2.0 (1H, m), 1.94 (2H, m), 1.76 (1H, m), 1.61 (2H, m), 1.55 (1H, m), 1.41 (2H, m), 1.38 (2H, m), 1.36 (1H, m), 1.35 (1H, m), 1.33 (2H, m), 1.17 (2H, m), 1.12 (2H, m), 1.04 (1H, m), 0.94 (3H, d, 3 J ¼ 6.1 Hz), 0.87 (6H, d, 3J ¼ 6.4 Hz), 0.63 (3H, s). 13C RMN (100 MHz, CDCl3): d 143.9, 143.3, 138.7, 128.1, 128.1, 126.2, 122.9, 120.5, 74.2, 61.3, 56.6, 56.11, 45.7, 40.4 (x2), 39.4, 36.1, 36.0, 29.4, 27.9, 27.5, 23.8, 23.6, 22.7, 22.5, 22.3, 18.8, 11.9. MS (ESIþ) m/z 431 ((MþNH4)þ, 30), 391 (100), 242 (18). Anal. Calcd for [C28H44O2]: C, 81.55, H, 10.68. Found: C, 81.37, H, 10.53. HPLC: Column Deltapack® C18, Absorbance: 300 nm, (Eluant: CH3CN/H2O 85/15). Concentration: 10 mg/mL, r.T. ¼ 17.39 min. 4.1.29. Compound 33 To a solution of 26c (80 mg, 0.14 mmol, 1 equiv.) in dry MeOH (5 mL) was added resin Dowex 50WX2 (200 mg). The reaction mixture was heated at 60  C. After being stirred for 2 h, the crude product was filtered over a pad of silica (elution with EtOAc). After concentration in vacuo, the residue was purified by flash chromatography (Cyclohexane/AcOEt: 1/1) to give the compound 33 [48 mg, 0.11 mmol, 82%, amorphous solid]. 1 Rf ¼ 0.14 (Cyclohexane/AcOEt 1/1). [a]25 D þ53.1 (c 0.05, CHCl3). H RMN (400 MHz, CDCl3): d 7.29 (1H, t, 3J ¼ 7.6 Hz), 7.20 (1H, s), 7.18 (1H, d, 3J ¼ 7.6 Hz), 7.13 (1H, d, 3J ¼ 7.5 Hz), 6.07 (1H, s), 4.93 (1H, dd, 3 J ¼ 3.6 Hz, 3J ¼ 8.2 Hz), 3.85 (2H, t, 3J ¼ 3.8 Hz), 2.89 (1H, d, 3 J ¼ 12.4 Hz), 2.10 (1H, m), 2.08 (1H, m), 2.0 (2H, m), 1.98 (2H, m), 1.78 (1H, m), 1.59 (2H, m), 1.58 (2H, m), 1.46 (1H, m), 1.43 (2H, m), 1.41 (1H, m), 1.38 (1H, m), 1.25 (2H, m), 1.23 (6H, s), 1.10 (2H, m), 0.97 (3H, d, 3J ¼ 6.3 Hz), 0.65 (3H, s). 13C RMN (100 MHz, CDCl3): d 144.0, 143.2, 138.9, 128.1, 128.0, 126.2, 123.0, 120.6, 74.3, 71.2, 61.4, 56.6, 56.2, 45.8, 44.4, 40.4, 36.4, 36.1, 30.1, 29.5, 29.3, 29.1, 27.6, 26.8, 23.6, 22.4, 18.8, 11.9. MS (ESIþ) m/z: 451.3 ((MþNa)þ, 100). Anal. Calcd for [C36H52O4]: C, 78.46, H, 10.35. Found: C, 78.35, H 10.26. HPLC: Column Deltapack® C18, Absorbance: 300 nm, (Eluant:CH3CN/H2O 8/2). Concentration: 10 mg/mL, r.T. ¼ 16.8 min. 4.1.30. Compound 34 To a solution of 27b (150 mg, 0.27 mmol, 1 equiv.) in dry MeOH (10 mL) was added resin Dowex 50WX2 (400 mg). The reaction mixture was heated at 60  C. After being stirred for 2 h, the crude product was filtered over a pad of silica (elution with EtOAc). After concentration in vacuo, the residue was purified by flash

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chromatography (Cyclohexane/AcOEt: 1/1) to give the compound 34 [92 mg, 0.21 mmol, 80%, amorphous solid]. Rf ¼ 0.14 (Cyclohexane/AcOEt: 1/1), [a]25 D 82.6 (c 0.1, CHCl3). IR (film, cm1): n 3352, 2944, 2871, 2232, 1723, 1653, 1602, 1433, 1376, 1240, 1163, 1049, 947, 708. 1H RMN (400 MHz, CDCl3): d 7.25 (1H, t, 3 J ¼ 7.3 Hz), 7.16 (1H, s), 7.14 (1H, d, 3J ¼ 8.6 Hz), 7.09 (1H, d, 3 J ¼ 7.5 Hz), 6.04 (1H, s), 4.89 (1H, dd, 3J ¼ 3.7 Hz, 3J ¼ 12.2 Hz), 3.80 (2H, t, 3J ¼ 4.8 Hz), 2.86 (1H, d, 3J ¼ 12.7 Hz), 2.09 (1H, m), 2.16 (1H, m), 1.98 (2H, m), 1.93 (1H, m), 1.91 (1H, m), 1.73 (1H, m), 1.59 (2H, m), 1.58 (1H, m), 1.57 (2H, m), 1.49 (6H, s), 1.41 (1H, m), 1.36 (1H, m), 1.31 (1H, m), 1.07 (3H, d, 3J ¼ 6.5 Hz), 0.62 (3H, s). 13C RMN (100 MHz, CDCl3): d 144.0, 142.8, 138.6, 128.0, 127.9, 126.1, 123.0, 120.8, 86.2, 81.1, 73.9, 65.2, 61.0, 56.0, 55.7, 45.6, 40.4, 40.2, 35.9, 31.7, 29.3, 27.3, 25.6, 23.4, 22.3, 19.1, 12.0. MS (ESIþ) m/z 470.3 ((Mþ2Na)þ, 27), 447.3 ((MþNa)þ, 100). Anal. Calcd for [C36H52O4]: C, 79.20, H, 9.50. Found: C, 75.89, H, 9.45. HPLC: Column Deltapack® C18, Absorbance: 300 nm, (Eluant:CH3CN/H2O 8/2). Concentration: 10 mg/mL, r.T. ¼ 15.9 min. 4.1.31. Compound 35 To a solution of disilylether 28 (250 mg, 0.4 mmol, 1 equiv.) in dry THF (20 mL) was added a solution of TBAF in THF (4.8 mL, 4.8 mmol, 12 equiv.). The yellow and translucent reaction mixture was stirred at room temperature for 24 h. The crude product was filtered over a pad of silica (elution with Cyclohexane/EtOAc 1/1). After concentration in vacuo, the residue was purified by a first flash chromatography (Cyclohexane/AcOEt: 1/1) and a second one (CH2Cl2/AcOEt: 8/2) to give the diol 35 [120 mg, 0.3 mmol, 75%, amorphous solid].  Rf ¼ 0.2 (cyclohexane/AcOEt 1/1). [a]D 25 ¼ þ12.3 (c ¼ 0.31 CHCl3). IR (film, cm1): n 2953, 2929, 2857, 2360, 2255, 2176, 2156, 2071, 2010, 1994, 1496, 1405, 1255, 1214, 1068, 837, 809, 730. 1H RMN (400 MHz, CDCl3): d 7.26 (1H, d, 3J ¼ 7.3 Hz), 7.19 (1H, s),7.16 (1H, d, 3J ¼ 7.3 Hz), 6.06 (1H, s), 4.68 (2H, s), 4.67 (2H, s), 2.89 (1H, m), 2.12 (1H, m), 2.06 (1H, m), 1.94 (2H, m), 1.76 (1H, m), 1.65 (2H, m), 1.61 (2H, m), 1.59 (2H, m), 1.41 (1H, m), 1.39 (2H, m), 1.36 (1H, m), 1.34 (1H, m), 1.33 (1H, m), 1.27 (2H, m), 0.96 (3H, d, 3J ¼ 6.1 Hz), 0.90 (6H, d, 3J ¼ 6.6 Hz), 0.65 (3H, s). 13C RMN (100 MHz, CDCl3): d 143.7, 138.9, 138.7, 136.6, 130.2, 129.4, 128.7, 119.9, 64.2, 63.7, 56.6; 56.1, 45.7, 40.3, 39.4, 36.0, 35.9, 29.4, 27.9, 27.5, 23.8, 23.5, 22.7, 22.4, 22.3, 18.8, 11.9. MS (ESIþ) m/z 421.3 ((MþNa)þ, 100). Anal. Calcd for [C27H42O2]: C, 81.35, H, 10.62. Found: C, 81.31, H, 10.58. HPLC: Column Deltapack® C18, Absorbance: 300 nm, (Eluant: CH3CN/H2O: 85/15). Concentration: 10 mg/mL, r.T. ¼ 15.18 min. 4.1.32. Compound 36 To a solution of 29 (300 mg, 0.41 mmol, 1 equiv.) in dry MeOH (19 mL) was added resin Dowex 50WX2 (770 mg). The reaction mixture was heated at 60  C. After being stirred for 2 h, the crude product was filtered over a pad of silica (elution with EtOAc). After concentration in vacuo, the residue was purified by flash chromatography (Cyclohexane/AcOEt: 1/1) to give the compound 36 [136 mg, 0.33 mmol, 81%, amorphous solid].  Rf ¼ 0.2 (cyclohexane/AcOEt: 1/1). [a]25 D ¼ þ33.1 (c 0.13, MeOH). IR (film, cm1): 3317, 2930, 2870, 2234, 1739, 1724, 1447, 1375, 1239, 1163, 1013, 947, 858. 1H RMN (400 MHz, CDCl3): d 7.32 (1H, d, 3 J ¼ 7.9 Hz), 7.25 (1H, s), 7.13 (1H, d, 3J ¼ 7.9 Hz), 6.08 (1H, s), 4.67 (4H, bs), 2.92 (1H, d, 3J ¼ 12.3 Hz), 2.23 (1H, m), 2.14 (1H, m), 2.05 (2H, m), 1.97 (1H, m), 1.76 (1H, m), 1.61 (2H, m), 1.57 (1H, m), 1.56 (2H, m), 1.49 (1H, m), 1.43 (6H, s), 1.39 (1H, m), 1.35 (1H, m), 1.10 (3H, d, 3J ¼ 6.3 Hz), 0.63 (3H, s). 13C RMN (100 MHz, CDCl3): d 143.2, 140.5, 138.3 (x2), 129.5, 128.6, 128.4, 121.6, 88.2, 80.2, 64.8, 63.2, 62.9, 56.8, 56.4, 46.4, 41.1, 36.8, 32.5 (x2), 30.1, 28.1, 26.2, 24.2, 23.1, 19.6, 12.5. MS (ESIþ) m/z 433.3 ((MþNa)þ, 100). Anal. Calcd for [C27H38O3]: C, 78.98, H, 9.33. Found: C, 78.89, H, 9.22.

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4.1.33. Compound 37 To a solution of disilylether 30 (100 mg, 0.16 mmol, 1 equiv.) in dry THF (5 mL) was added a solution of TBAF in THF (1.92 mL, 1.92 mmol, 12 equiv.). The yellow and translucent reaction mixture was stirred at room temperature for 24 h. The crude product was filtered over a pad of silica (elution with Cyclohexane/EtOAc 1/1). After concentration in vacuo, the residue was purified by a first flash chromatography (Cyclohexane/AcOEt: 1/1) and a second one (CH2Cl2/AcOEt:8/2) to give the diol 37 [48 mg, 0.12 mmol, 76%, amorphous solid]. Rf ¼ 0.22 (cyclohexane/AcOEt:1/1). IR (film, cm1): n 3317, 2949, 2928, 2868, 1656, 1590, 1465, 1377, 1330, 1188, 997, 799, 768, 735. 1  [a]D 25 ¼ þ78.2 (c ¼ 0,31 CHCl3). H RMN (400 MHz, CDCl3): d 7.23 3 (2H, m), 7.14 (1H, d, J ¼ 6.8 Hz), 6.21 (1H, s), 4.77 (2H, s, H), 4.73 (2H, s), 3.16 (2H, bs), 2.48 (1H, m), 2.13 (1H, m), 2.05 (1H, m), 1.97 (2H, m), 1.66 (1H, m), 1.64 (2H, m), 1.60 (2H, m), 1.57 (2H, m), 1.40 (1H, m), 1.38 (2H, m), 1.36 (1H, m), 1.35 (1H, m), 1.33 (1H, m), 1.25 (2H, m), 0.97 (3H, d, 3J ¼ 5.3 Hz), 0.90 (6H, d, 3J ¼ 6.3 Hz), 0.69 (3H, s). 13C RMN (100 MHz, CDCl3): d 144.2, 139.9, 139.0, 137.4, 130.5, 128.1, 127.8, 118.7, 64.7, 59.9, 56.7, 55.9, 45.8, 40.4, 39.5, 36.1, 36.0, 29.7, 27.9, 27.6, 23.9, 23.5, 22.8, 22.5, 22.4, 18.8, 12.0. MS (ESIþ) m/z 451.3 ((MþNa)þ, 100). Anal. Calcd for [C36H52O4]: C, 78.46, H, 10.35. Found: C, 78.35, H 10.26. HPLC: Column Deltapack® C18, Absorbance: 300 nm, (CH3CN/H2O: 85/15). Concentration: 10 mg/mL, r.T. ¼ 16.32 min. 4.1.34. Compound 38 To a solution of 31 (150 mg, 0.21 mmol, 1 equiv.) in dry MeOH (10 mL) was added resin Dowex 50WX2 (385 mg). The reaction mixture was heated at 60  C. After being stirred for 2 h, the crude product was filtered over a pad of silica (elution with EtOAc). After concentration in vacuo, the residue was purified by flash chromatography (Cyclohexane/AcOEt: 1/1) to give the compound 38 [136 mg, 0.33 mmol, 81%, amorphous solid]. Rf ¼ 0.2 (cyclohexane/AcOEt: 1/1). IR (film, cm1): n 3312, 2933, 2860, 2231, 1725, 1443, 1375, 1236, 1165, 1013, 947, 756. 1H RMN (400 MHz, CDCl3): d 7.36 (1H, d, 3J ¼ 7.4 Hz), 7.19 (1H, t, 3J ¼ 7.4 Hz), 7.15 (1H, d, 3J ¼ 7.4 Hz), 6.12 (1H, s), 4.69 (2H, s), 4.67 (2H, s), 2.43 (1H, d, 3J ¼ 11.8 Hz), 2.21 (1H, m), 2.17 (1H, m), 2.00 (2H, m), 1.88 (1H, m), 1.71 (1H, m), 1.63 (2H, m), 1.54 (1H, m), 1.52 (2H, m), 1.46 (1H, m), 1.44 (6H, s), 1.36 (1H, m), 1.32 (1H, m), 1.12 (3H, d, 3 J ¼ 6.3 Hz), 0.61 (3H, s). 13C RMN (100 MHz, CDCl3): d 143.9, 139.7, 138.8, 137.3, 130.4, 129.0, 128.1, 121.2, 88.6, 88.2, 64.6, 63.4, 63.2, 56.1, 55.6, 45.6, 40.1, 35.8, 31.7 (x2), 29.5, 27.3, 25.6, 23.3, 22.2, 19.1, 12.0. MS (ESIþ) m/z 433.2 ((MþNa)þ, 100). Anal. Calcd for [C27H38O3]: C, 78.98, H, 9.33. Found: C, 78.52, H, 9.15. 4.2. Biological evaluations 4.2.1. Binding assays to VDR Measurement of binding to the human recombinant VDR was done using purified human recombinant receptor from Sf9 human cells, following the Ross protocol [52]. Radiolabeled [3H]1a,25(OH)2vitamin D3, the reference compound, was used at a final concentration of 0.3 nM. The specific ligand ([3H]1a,25-(OH)2vitamin D3) binding to receptor is defined as the difference between the total binding and the nonspecific binding determined in the presence of an excess of unlabeled ligand (1a,25-(OH)2vitamin D3). Analogues compounds were solubilized in DMSO and were tested at a concentration of 105 M, incubated for 20 h at 4  C. The free [3H]1a,25-(OH)2vitamin D3 was measured by scintillation counting. The results are expressed as a percent inhibition of control specific bonding obtained in the presence of the test compounds. The experiments were carried out in duplicate. All assays were performed by CEREP in the study number 920819.

4.2.2. Induction of HL-60 cell differentiation The analogues compounds were incubated with HL-60 cells at 37  C for 144 h. Cells were then incubated for 4 h with Wst-1 reagent and the absorbency was measured in each well at 450 nM and 620 nM, following the Marcinkowska procedure[53]. Two independent experiments were performed and the results are presented as the concentration of test substances allowing a 50% inhibition of proliferation (IC50). The experiments were carried out in duplicate. All assays were performed by CELLIS Pharma in the study number CP-2004061.1. Acknowledgments Dr. C. Harpey, Dr. A. Le Ridant and Les Laboratoires Servier are gratefully acknowledged for financial support and for a doctoral fellowship to E. Thomas. Appendix A. Supplementary data Supplementary data related to this article can be found at http:// dx.doi.org/10.1016/j.ejmech.2014.07.037. References [1] R. Bouillon, W.H. Okamura, A.W. Norman, Structure-function relationships in the vitamin D endocrine system, Endocr. Rev. 16 (1995) 200e257. [2] R. Bouillon, A.W. Norman, J.R. Pasqualini (Eds.), Vitamin D, J. Steroid Biochem, vols. 89e90, Elsevier, 2004, pp. 1e633. [3] second ed., in: D. Feldman, J.W. Pike, F.H. Glorieux (Eds.), Vitamin D, vols. 1 and 2, Elsevier, Academic Press, 2005, pp. 1e1892. [4] A.J. Brown, E. Slatopolsky, Vitamin D analogs: therapeutic applications and mechanisms for selectivity, Mol. Asp. Med. 29 (2008) 433e452. [5] K. Casteels, R. Bouillon, M. Waer, C. Mathieu, Immunomodulatory effects of 1,25-dihydroxyvitamin D3, Curr. Opin. Nephrol. Hypertens. 4 (1995) 313e318. [6] A.S. Dusso, A.J. Brown, E. Slatopolsky, Vitamin D, Am. J. Physiol. Renal Physiol. 289 (2005) F8eF28. [7] K.D. Crew, M.D. Gammon, S.E. Steck, D.L. Hershman, S. Cremers, E. Dworakowski, E. Shane, M.B. Terry, M. Desai, S. Teitelbaum, A.I. Nugut, R.M. Santella, Association between plasma 25-hydroxyvitamin D and breast cancer risk, Cancer Prev. Res. 2 (2009) 598e604. [8] H.S. Cross, G. Bises, D. Lechner, T. Manhardt, E. Kallay, The vitamin D endocrine system of the gut-its possible role in colorectal cancer prevention,, J. Steroid Biochem. Mol. Biol. 97 (2005) 121e128. [9] M. Jenab, H.B. Bueno-de-Mesquita, P. Ferrari, F.J.B. van Duijnhoven, T. Norat, T. Pischon, E.H.J.M. Jansen, N. Slimani, G. Byrnes, S. Rinaldi, A. Tjonneland, A. Olsen, K. Overvad, M.C. Boutron-Ruault, F. Clavel-Chapelon, S. Morois, R. Kaaks, J. Linseisen, H. Boeing, M.M. Bergmann, A. Trichopoulou, G. Misirli, D. Trichopoulos, F. Berrino, P. Vineis, S. Panico, D. Palli, R. Tumino, M.M. Ros, C.H. van Gils, P.H. Peeters, M. Brustad, E. Lund, M.-J. Tormo, E. Ardanaz, L. Rodriguez, M.-J. Sanchez, M. Dorronsoro, C.A. Gonzalez, G. Hallmans, R. Palmqvist, A. Roddam, T.J. Key, K.-T. Khaw, P. Autier, P. Hainaut, E. Riboli, Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations: a nested case-control study, Br. Med. J. 340 (2010) b5500.
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