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Diels-alder additions of 1,3-dienes to propargylic alcohols catalyzed by the Wilkinson's catalyst
Journal of Molecular Catalysis, 60 (1990) 59-63
59
DIELS-ALDER ADDITIONS OF 1,3-DIENES TO PROPARGYLIC ALCOHOLS CATALYZED BY THE WILKINSON’S CATALYST RENKO ZAFIARISOA DOLOR and PIERRE VOGEL* Section de Chimie de I Universitc! de Lausanne, 2, rue de la Barre, CH 1005Lausann.e (Switzerland) (Received June 15,198Q; accepted August 25,1969)
The Wilkinson’s catalyst (Rh(Ph,P),Cl) was found to catalyze DielsAlder reactions of propynol (la), but-3-yn-2-01 (lb), 2-methylbut-3-yn-2-01 (lc), but-2-yn-1,sdiol (ld) and hept-6-en-3-yn-2-01 (le) to 2,3dimethylbutadiene, giving mixtures of the corresponding cyclohexa-1,C dienes and benzylic alcohols. The solvent played a decisive role in the success of the cycloadditions, the best results being observed with CF,CH,OH. Under these conditions, isoprene added to la with a slight paru regioselectivity gave a 3:4 mixture of 5-methylcyclohexa-1,4-diene-l-methanol (6) and 4methylcyclohexa-l,Cdiene-l-methanol (7).
Introduction Under thermal conditions, propargylic alcohols react only sluggishly in Diels-Alder additions [ll. In the presence of strong acids, and if adequate substituted derivatives are used, propargylic c, allenyl cation intermediates might be generated and undergo concurrent 12 + 21, [4+ 21 and [4+ 33 cycloadditions to well-chosen l,&dienes 121. Since the pioneering work of Schrauzer on the Ni-catalyzed cycloadditions of norbornadiene to tolane 133, few examples of transition metal catalyzed 14 + 2lcycloadditions of nonactivated internal alkynes to l,&dienes have been reported thus far 141. Recently, Matsuda et al. [5] showed that terminal alkynes can add to 2-substituted l,&dienes (CHzClz, 100 “C) in the presence of a cationic Rh(1) complex. Since the Wilkinson’s catalyst (Rh(Ph,P)&l) can induce the cyclotrimerization of alkynes 163, we have explored its potential as a catalyst for the Diels-Alder addition and report here our preliminary results. ResuIts and discussion We have found (Table 1) that the Diels-Alder additions of propargylic alcohol la and its derivatives lb-e 2,3_dimethylbutadiene (2) are catalyzed *Author to whom correspondence should be addressed. 0304-5102/QO/$3.50
@ Elsevier Sequoia/Printed in The Netherlands
60 TARI.& 1 Isolated yields of adduct mixtures 3 + 4(+6) for reactions (60 “C, 2 h) of 1 (0.3 M) +2 (0.45 M) in CF,CH,OH in the presence of 5 moI% Rh(Ph,P),Cl DienophiIe 1
Yield of 3 + 4”*b (%)
(a) R,=Re=&=H (b) R1=Me, Re=Ra=H (c)Ri=&=Me,R,=H (d) R,=R,=H, &=CH,OH (e) R, = Me, R, = H, R3 = CH,CH=CH2
46 36 30 22 64
1:l’ 2:3 [71 3:l [81”-d
W-oduct ratio determined by 250 MHz ‘H NMR of the purified mixture (column chromatography on silica gel, distillation in uocw 1. bNo cycloaddition was observed in the absence of catalyst. ‘see Aldrich catalog, No. 19,999.0 dWhen 2 was added dropwise to the reaction mixture, trimeriaation of lc becamethe major plXXeS8. Vch m.p. 66”C, 8ee [91. ‘In the presence of 1% of Rh(Ph,),Cl, the reaction required 2 days for similar conversion rate and yields.
by Rh(Ph3P)$l. The corresponding cyclohexa-1,4-dienes 3a-e are obtained together with their didehydrogenated products 4a-e, respectively. With hept-6-en-3-y-n-2-01 (le) only,the 12 + 21-cycloaddition giving the cyclobutene derivatives 5 (1: 1 mixture of two diastereomers) was a competitive process. Complete aromatization of the adduct mixtures could be achieved nearly quantitatively on treatment with a catalytic amount of 5% Pd on charcoal in toluene at 20 “C (3 h) [ 73. When dichlorodicyanobenzoquinone was used for the oxidation, only decomposition was observed. Interestingly, the Pd/Ccatalyzed aromatization was not accompanied by double bond migration of the allylic derivative 4e. Noteworthy also was the fact that this thermodynamically favoured isomerization does not occur with the Wilkinson’s catalyst. In the case of le + 2, no products arising from reaction of the alkene moiety of le could be detected. The structures of 3, 4 and 5 were obtained by their spectral data and, in the case of 4a-d, by comparison with published data (see references in Table 1).
4 1
2
3
4
Contrary to the conditions used by Matsuda et al. 151, both terminal (la, b, c) and internal alkynes (Id, e) undergo Diels-Alder additions to 2,3_dimethylbutadiene in the presence of the Wilkinson’s catalyst. This
61
catalytic process, however, was limited to propargylic alcohols as we found that the cycloadditions of propargylic acetate, propynoic acid, methyl propynoate, phenylacetylene, pent-1-yne and allylic alcohol did not add to 2 in the presence of Rh(Ph,P),Cl. The nature of the l,&dienes also affects the reactions. For instance, no cycloadditions could be observed with la and cyclopentadiene, cyclohexadiene, furan and l-substituted butadienes such as piperylene and 1-methoxy-3-(trimethylsilyloxy)butadiene. Nevertheless, isoprene (0.5 M) added to la (0.5 M) in CFBCHzOH (6O”C, 2 h) afforded a 3:4 mixture of cyclohexa-1,4-dienes 6 and 7 [lOI (70%). In this case, only traces of the corresponding benzylic alcohols were formed.
?H
T\ + -v la
6
+Ji?J OH
7
The nature of the solvent plays an important role in the F&(I)-catalyzed cycloadditions. For instance, no reaction was observed for le + 2 in CH,CN, THF or CHzClz (boiling of the solvents, 2 days). In EtOH, the [4+ 2]cycloaddition was much slower than in CF3CH20H. After 48 h at 80 “C, 11% of 8 was isolated as the unique product of cyclocondensation. In MeOH (65 “C, 48 h), a mixture of 8 (18%) and 9 (18%) was obtained. In MeOH/H20 4: 1 (65 “C, 48 h), 8 and 9 were isolated in 34 and 10% yields, respectively. The reduction of the benzylic alcohol 4e could not be suppressed by addition of 1-phenylethanol to the reaction mixture. EtSN and NaHC03 were found to inhibit the Rh-catalyzed cycloadditions in MeOH. In (CF&CHOH (6O”C, 48 h), 8 was the unique product isolated in 68% yield; 8 was also formed in CFBCHZOHafter prolonged heating (>6 h).
62
The results presented here suggest that other combinations of 1,3dienes, dienophiles, transition metal complexes and solvents should be explored [ 11 I to force difficult thermal Diels-Alder additions to occur.
Experimental section For general experimental procedure, see 1121. Hept-6-en-3-yn-2-01 (le) But-3-yn-2-01 (10 g, 0.142 mol) was added dropwise to a saturated soln. of NaCl in Hz0 containing CuCl (1 g) under Ar atmosphere. After heating to 60 “C, the pH was adjusted to 7.5-8.5 with 40% aq. NaOH, and ally1 chloride (16 g, 0.21 mmol) was added slowly while maintaining the pH between 7.5 and 8.5. After stirring at 60 “C for 1 h, the mixture was filtered and extracted with Eta0 (30 ml, twice). The organic phases were combined, washed successively with sat. aq. NH&l solution and H20, and dried (MgSO,). Distillation yielded 13.2 g (84%), colourless liquid, b.p. 58 “C/15 torr. ‘HNMR (CDCI,): 6 = 5.42-5.87 (m, H-6), 4.85-5.20 (m, 2H, H-7), 4.35 (q, J = 6.5 Hz, H-2), 2.77 (m, 2H, H-2), 2.17 (s, OH), 1.23 (d, J = 6.5, CH,). Example of cycloaddition of 2,3-dimethylbutadiene (2) to le A mixture of le (0.66 g, 6mmol), 2,3_dimethylbutadiene (2, 0.74g, 9mmol), Rh(Ph,P),Cl (0.277 g, 0.3mmol) and CF&H20H (20 ml) was heated to 60 “C under Ar atmosphere for 2 h. The solvent was evaporated and the residue purified by column chromatography on silica gel (150 g, EtaO/petroleum ether 1: 9), yielding 0.74 g (64%) colourless oil. The 12: 1: 12 mixture of 3e: 4e: 5 was dissolved in toluene (20 ml) and stirred with 5% Pd/C (0.1 g) at 20 “C for 3 h. After solvent evaporation, the residue composed of 4e and 5 was separated by bulb-to-bulb distillation in uacuo. Characteristics of (2allyL4,5dimethylphenyl)ethanol (4e) Colourless oil, b.p. 95 C/O.01 torr, W (EtOH): A,, = 207 (E = 19300), 268 (600); IR cm-’ (CHCI,): 3600,3450,3260,3080,3000,2975,2920,2865, 1625, 1500, 1450, 1370; ‘HNMR ppm (CDCI,): 6 = 7.31 (br. s, lH), 6.94 (br. s, lH), 6.00 (ddt, lH, J= 17.0, 10.0, 6.0Hz), 5.13 (q, lH, J= 6.2Hz), 5.07 (dm, lH, J= 17.0, 1.8Hz), 5.01 (dm, J= 10.0, 1.8Hz), 3.40 (br. dt, 2H, J=6.0, l.OHz), 2.27, 2.25 (2s, 6H, 2Me), 1.47 (d, 3H, J=6.2Hz, CH,); “CNMR ppm (CDCI,): 8 = 140.9, 137.9 (2s), 135.6 (d), 133.2 (s), 131.1 (d), 130.6 (s), 126.3 (d), 115.4 (t), 66.0 (d), 36.2 (t), 24.3, 19.3, 19.2 (3q). Characteristics of (LRS, 3’RS) or URS, 3’SR)-2’-ally&3’-methyl-3’isopropenylcyclobuten-1 ‘-yl Iethanol (5) One of the diastereomers could be obtained pure in low yield by column chromatography on silica gel (EtzO/petroleum ether 1: 99 to 5 : 95); colourless oil, b.p. 6O”C/O.O1 torr, W (EtOH): A,,= 201 (E = 4750), 227 (2800), 280
63
(sh, 800); IR cm-l (CH&): 3600, 3250, 3080, 3000, 2970, 2920, 2870, 1635, 1447, 1370; ‘HNMXppm (CDC13): S=5.85 (ddt, lH, J=17.0, 10.0, 6.8Hz), 5.07 (dq, lH, J=17.0, 1.8Hz), 5.00 (dq, lH, J=lO.O, 1.8Hz, CH&), 4.75 (m, 2H, CH,C=Me), 4.49 (br. q, lH, J=6.5Hz, CH-OH), 2.85 and 2.73 (2ddt, 2H, J= 16.0, 6.8, 1.5Hz, CH&ZH=CH,); 2.37 and 2.06 (2 br. d, J = 12.0 Hz, H,C of cyclobutene), 1.70 (t, 3H, J = 1.0 Hz, CH3-C=CH&, 1.49 (br. s, OH), 1.27 (s, 3H, Me), 1.24 (d, 3H, J = 6.5Hz, C&-CHOH); %NMR ppm (CDC13): 6 = 149.3, 144.8, 141.5 (3s), 135.5 (d), 115.8 (t), 110.8 (s), 109.5 (t), 64.5 (d), 38.8 (t), 31.7 (t), 22.2, 21.3, 19.3 (3q).
References 1 J. Sauer, Angew. Chem. Znt. Ed. Engl., 5 (1966) 211; H. Wollweber, Dick-Alder Beaktion, Georg Thieme Verlag, Stuttgart, 1972; J. Sauer and R. Su&mann, Angew. Gem. Znt. Ed. Engl., 19 (1980) 779. 2 H. Mayr and F. Schiitz, Tetrahednx L&t., 22 (1981) 925; H. Mayr, E. Wilhelm end C. KaIiba, J. Chem. Sot. Chem. Commun., (1981) 683; H. Mayr end E. B¨, Tetrahedron Z.&t., 24 (1983) 357; see also P. G. Gassmann and S. P. Chavan, ibid., 29 (1988) 3407, and references cited therein. 3 G. N. Schrauzer and P. Glockner, Chem. Ber. 97 (1964) 2451; G. N. Schrauzer, Adv. Catal. 18 (1968) 373; see also: J. E. Lyons, H. K. Myers and A. Schneider, J. Chem. Sot., Chem Commun., (1978) 636,633; Ann. N.Y. Acad. Sci., 333 (1980) 273. 4 N. E. Schore, Chem. Rev., 88 (1988) 1081; A. Carbonaro, A. Greco and G. DaII’Asta, J. Org. Chem., 33 (1968) 3948; J. Organometull. Chem., 20 (1969) 177; J. P. Gen& and J. Ficini, Tetrahedron Mt., (1979) 1499; H. Tom Diek and R. Diercke, Agnew. Chem. Znt. Ed. En& 22 (1983) 778; Angew. Chem. Suppl., (1983) 1138; K. Mach, H. Ant~piueovB, L. PetrueovB, F. Ture&k, V. Hanti, P. Sedmera and J. SchramI, J. Organometall. Chem., 289 (1985) 331; H. Tom Diek, M. MaIlien and R. Die&s, J. Mol. Cat& 51 (1989) 53 and references cited therein. 5 I. Matsuda, M. Shibata, S. Sato and Y. Izumi, Tetrahedron Z.&t., 28 (1987) 3361. 6 S. J. Neeson and P. J. Stevenson Tetrahedron Lett., 29 (1988) 813. 7 A. R. Stein, R. D. Dawe and J. R. Sweeb, Can. J. Chem., 63 (1985) 3442. 8 G. Bourgeois end R. LaIande, Bull. Sot. Chim. Fr., (1972) 4324. 9 D. J. Brickwood, W. D. Ollis, J. S. Stephanotov and J. F. Stoddart, J. Chem. Sot., Perkin Trans. 1 (1978) 1398. 10 F. Sugawara, T. Sugiyama, A. Kobayaehi end K. Yemaehita, Agric. Bill. Chem., 42 (1978) 847. 11 See also P. Vioget, P. Vogel and R. RouIet, Angew. Chem. Suppl., (1982) 1128; P. Vioget, M. Bonivento, R. Roulet and P. Vogel, Helu. Chim. Acta, 67 (1984) 1638. 12 J. Wagner, E. Vieira and P. Vogel, Helv. Chim. Acta, 71 (1988) 624.
59
DIELS-ALDER ADDITIONS OF 1,3-DIENES TO PROPARGYLIC ALCOHOLS CATALYZED BY THE WILKINSON’S CATALYST RENKO ZAFIARISOA DOLOR and PIERRE VOGEL* Section de Chimie de I Universitc! de Lausanne, 2, rue de la Barre, CH 1005Lausann.e (Switzerland) (Received June 15,198Q; accepted August 25,1969)
The Wilkinson’s catalyst (Rh(Ph,P),Cl) was found to catalyze DielsAlder reactions of propynol (la), but-3-yn-2-01 (lb), 2-methylbut-3-yn-2-01 (lc), but-2-yn-1,sdiol (ld) and hept-6-en-3-yn-2-01 (le) to 2,3dimethylbutadiene, giving mixtures of the corresponding cyclohexa-1,C dienes and benzylic alcohols. The solvent played a decisive role in the success of the cycloadditions, the best results being observed with CF,CH,OH. Under these conditions, isoprene added to la with a slight paru regioselectivity gave a 3:4 mixture of 5-methylcyclohexa-1,4-diene-l-methanol (6) and 4methylcyclohexa-l,Cdiene-l-methanol (7).
Introduction Under thermal conditions, propargylic alcohols react only sluggishly in Diels-Alder additions [ll. In the presence of strong acids, and if adequate substituted derivatives are used, propargylic c, allenyl cation intermediates might be generated and undergo concurrent 12 + 21, [4+ 21 and [4+ 33 cycloadditions to well-chosen l,&dienes 121. Since the pioneering work of Schrauzer on the Ni-catalyzed cycloadditions of norbornadiene to tolane 133, few examples of transition metal catalyzed 14 + 2lcycloadditions of nonactivated internal alkynes to l,&dienes have been reported thus far 141. Recently, Matsuda et al. [5] showed that terminal alkynes can add to 2-substituted l,&dienes (CHzClz, 100 “C) in the presence of a cationic Rh(1) complex. Since the Wilkinson’s catalyst (Rh(Ph,P)&l) can induce the cyclotrimerization of alkynes 163, we have explored its potential as a catalyst for the Diels-Alder addition and report here our preliminary results. ResuIts and discussion We have found (Table 1) that the Diels-Alder additions of propargylic alcohol la and its derivatives lb-e 2,3_dimethylbutadiene (2) are catalyzed *Author to whom correspondence should be addressed. 0304-5102/QO/$3.50
@ Elsevier Sequoia/Printed in The Netherlands
60 TARI.& 1 Isolated yields of adduct mixtures 3 + 4(+6) for reactions (60 “C, 2 h) of 1 (0.3 M) +2 (0.45 M) in CF,CH,OH in the presence of 5 moI% Rh(Ph,P),Cl DienophiIe 1
Yield of 3 + 4”*b (%)
(a) R,=Re=&=H (b) R1=Me, Re=Ra=H (c)Ri=&=Me,R,=H (d) R,=R,=H, &=CH,OH (e) R, = Me, R, = H, R3 = CH,CH=CH2
46 36 30 22 64
1:l’ 2:3 [71 3:l [81”-d
W-oduct ratio determined by 250 MHz ‘H NMR of the purified mixture (column chromatography on silica gel, distillation in uocw 1. bNo cycloaddition was observed in the absence of catalyst. ‘see Aldrich catalog, No. 19,999.0 dWhen 2 was added dropwise to the reaction mixture, trimeriaation of lc becamethe major plXXeS8. Vch m.p. 66”C, 8ee [91. ‘In the presence of 1% of Rh(Ph,),Cl, the reaction required 2 days for similar conversion rate and yields.
by Rh(Ph3P)$l. The corresponding cyclohexa-1,4-dienes 3a-e are obtained together with their didehydrogenated products 4a-e, respectively. With hept-6-en-3-y-n-2-01 (le) only,the 12 + 21-cycloaddition giving the cyclobutene derivatives 5 (1: 1 mixture of two diastereomers) was a competitive process. Complete aromatization of the adduct mixtures could be achieved nearly quantitatively on treatment with a catalytic amount of 5% Pd on charcoal in toluene at 20 “C (3 h) [ 73. When dichlorodicyanobenzoquinone was used for the oxidation, only decomposition was observed. Interestingly, the Pd/Ccatalyzed aromatization was not accompanied by double bond migration of the allylic derivative 4e. Noteworthy also was the fact that this thermodynamically favoured isomerization does not occur with the Wilkinson’s catalyst. In the case of le + 2, no products arising from reaction of the alkene moiety of le could be detected. The structures of 3, 4 and 5 were obtained by their spectral data and, in the case of 4a-d, by comparison with published data (see references in Table 1).
4 1
2
3
4
Contrary to the conditions used by Matsuda et al. 151, both terminal (la, b, c) and internal alkynes (Id, e) undergo Diels-Alder additions to 2,3_dimethylbutadiene in the presence of the Wilkinson’s catalyst. This
61
catalytic process, however, was limited to propargylic alcohols as we found that the cycloadditions of propargylic acetate, propynoic acid, methyl propynoate, phenylacetylene, pent-1-yne and allylic alcohol did not add to 2 in the presence of Rh(Ph,P),Cl. The nature of the l,&dienes also affects the reactions. For instance, no cycloadditions could be observed with la and cyclopentadiene, cyclohexadiene, furan and l-substituted butadienes such as piperylene and 1-methoxy-3-(trimethylsilyloxy)butadiene. Nevertheless, isoprene (0.5 M) added to la (0.5 M) in CFBCHzOH (6O”C, 2 h) afforded a 3:4 mixture of cyclohexa-1,4-dienes 6 and 7 [lOI (70%). In this case, only traces of the corresponding benzylic alcohols were formed.
?H
T\ + -v la
6
+Ji?J OH
7
The nature of the solvent plays an important role in the F&(I)-catalyzed cycloadditions. For instance, no reaction was observed for le + 2 in CH,CN, THF or CHzClz (boiling of the solvents, 2 days). In EtOH, the [4+ 2]cycloaddition was much slower than in CF3CH20H. After 48 h at 80 “C, 11% of 8 was isolated as the unique product of cyclocondensation. In MeOH (65 “C, 48 h), a mixture of 8 (18%) and 9 (18%) was obtained. In MeOH/H20 4: 1 (65 “C, 48 h), 8 and 9 were isolated in 34 and 10% yields, respectively. The reduction of the benzylic alcohol 4e could not be suppressed by addition of 1-phenylethanol to the reaction mixture. EtSN and NaHC03 were found to inhibit the Rh-catalyzed cycloadditions in MeOH. In (CF&CHOH (6O”C, 48 h), 8 was the unique product isolated in 68% yield; 8 was also formed in CFBCHZOHafter prolonged heating (>6 h).
62
The results presented here suggest that other combinations of 1,3dienes, dienophiles, transition metal complexes and solvents should be explored [ 11 I to force difficult thermal Diels-Alder additions to occur.
Experimental section For general experimental procedure, see 1121. Hept-6-en-3-yn-2-01 (le) But-3-yn-2-01 (10 g, 0.142 mol) was added dropwise to a saturated soln. of NaCl in Hz0 containing CuCl (1 g) under Ar atmosphere. After heating to 60 “C, the pH was adjusted to 7.5-8.5 with 40% aq. NaOH, and ally1 chloride (16 g, 0.21 mmol) was added slowly while maintaining the pH between 7.5 and 8.5. After stirring at 60 “C for 1 h, the mixture was filtered and extracted with Eta0 (30 ml, twice). The organic phases were combined, washed successively with sat. aq. NH&l solution and H20, and dried (MgSO,). Distillation yielded 13.2 g (84%), colourless liquid, b.p. 58 “C/15 torr. ‘HNMR (CDCI,): 6 = 5.42-5.87 (m, H-6), 4.85-5.20 (m, 2H, H-7), 4.35 (q, J = 6.5 Hz, H-2), 2.77 (m, 2H, H-2), 2.17 (s, OH), 1.23 (d, J = 6.5, CH,). Example of cycloaddition of 2,3-dimethylbutadiene (2) to le A mixture of le (0.66 g, 6mmol), 2,3_dimethylbutadiene (2, 0.74g, 9mmol), Rh(Ph,P),Cl (0.277 g, 0.3mmol) and CF&H20H (20 ml) was heated to 60 “C under Ar atmosphere for 2 h. The solvent was evaporated and the residue purified by column chromatography on silica gel (150 g, EtaO/petroleum ether 1: 9), yielding 0.74 g (64%) colourless oil. The 12: 1: 12 mixture of 3e: 4e: 5 was dissolved in toluene (20 ml) and stirred with 5% Pd/C (0.1 g) at 20 “C for 3 h. After solvent evaporation, the residue composed of 4e and 5 was separated by bulb-to-bulb distillation in uacuo. Characteristics of (2allyL4,5dimethylphenyl)ethanol (4e) Colourless oil, b.p. 95 C/O.01 torr, W (EtOH): A,, = 207 (E = 19300), 268 (600); IR cm-’ (CHCI,): 3600,3450,3260,3080,3000,2975,2920,2865, 1625, 1500, 1450, 1370; ‘HNMR ppm (CDCI,): 6 = 7.31 (br. s, lH), 6.94 (br. s, lH), 6.00 (ddt, lH, J= 17.0, 10.0, 6.0Hz), 5.13 (q, lH, J= 6.2Hz), 5.07 (dm, lH, J= 17.0, 1.8Hz), 5.01 (dm, J= 10.0, 1.8Hz), 3.40 (br. dt, 2H, J=6.0, l.OHz), 2.27, 2.25 (2s, 6H, 2Me), 1.47 (d, 3H, J=6.2Hz, CH,); “CNMR ppm (CDCI,): 8 = 140.9, 137.9 (2s), 135.6 (d), 133.2 (s), 131.1 (d), 130.6 (s), 126.3 (d), 115.4 (t), 66.0 (d), 36.2 (t), 24.3, 19.3, 19.2 (3q). Characteristics of (LRS, 3’RS) or URS, 3’SR)-2’-ally&3’-methyl-3’isopropenylcyclobuten-1 ‘-yl Iethanol (5) One of the diastereomers could be obtained pure in low yield by column chromatography on silica gel (EtzO/petroleum ether 1: 99 to 5 : 95); colourless oil, b.p. 6O”C/O.O1 torr, W (EtOH): A,,= 201 (E = 4750), 227 (2800), 280
63
(sh, 800); IR cm-l (CH&): 3600, 3250, 3080, 3000, 2970, 2920, 2870, 1635, 1447, 1370; ‘HNMXppm (CDC13): S=5.85 (ddt, lH, J=17.0, 10.0, 6.8Hz), 5.07 (dq, lH, J=17.0, 1.8Hz), 5.00 (dq, lH, J=lO.O, 1.8Hz, CH&), 4.75 (m, 2H, CH,C=Me), 4.49 (br. q, lH, J=6.5Hz, CH-OH), 2.85 and 2.73 (2ddt, 2H, J= 16.0, 6.8, 1.5Hz, CH&ZH=CH,); 2.37 and 2.06 (2 br. d, J = 12.0 Hz, H,C of cyclobutene), 1.70 (t, 3H, J = 1.0 Hz, CH3-C=CH&, 1.49 (br. s, OH), 1.27 (s, 3H, Me), 1.24 (d, 3H, J = 6.5Hz, C&-CHOH); %NMR ppm (CDC13): 6 = 149.3, 144.8, 141.5 (3s), 135.5 (d), 115.8 (t), 110.8 (s), 109.5 (t), 64.5 (d), 38.8 (t), 31.7 (t), 22.2, 21.3, 19.3 (3q).
References 1 J. Sauer, Angew. Chem. Znt. Ed. Engl., 5 (1966) 211; H. Wollweber, Dick-Alder Beaktion, Georg Thieme Verlag, Stuttgart, 1972; J. Sauer and R. Su&mann, Angew. Gem. Znt. Ed. Engl., 19 (1980) 779. 2 H. Mayr and F. Schiitz, Tetrahednx L&t., 22 (1981) 925; H. Mayr, E. Wilhelm end C. KaIiba, J. Chem. Sot. Chem. Commun., (1981) 683; H. Mayr end E. B¨, Tetrahedron Z.&t., 24 (1983) 357; see also P. G. Gassmann and S. P. Chavan, ibid., 29 (1988) 3407, and references cited therein. 3 G. N. Schrauzer and P. Glockner, Chem. Ber. 97 (1964) 2451; G. N. Schrauzer, Adv. Catal. 18 (1968) 373; see also: J. E. Lyons, H. K. Myers and A. Schneider, J. Chem. Sot., Chem Commun., (1978) 636,633; Ann. N.Y. Acad. Sci., 333 (1980) 273. 4 N. E. Schore, Chem. Rev., 88 (1988) 1081; A. Carbonaro, A. Greco and G. DaII’Asta, J. Org. Chem., 33 (1968) 3948; J. Organometull. Chem., 20 (1969) 177; J. P. Gen& and J. Ficini, Tetrahedron Mt., (1979) 1499; H. Tom Diek and R. Diercke, Agnew. Chem. Znt. Ed. En& 22 (1983) 778; Angew. Chem. Suppl., (1983) 1138; K. Mach, H. Ant~piueovB, L. PetrueovB, F. Ture&k, V. Hanti, P. Sedmera and J. SchramI, J. Organometall. Chem., 289 (1985) 331; H. Tom Diek, M. MaIlien and R. Die&s, J. Mol. Cat& 51 (1989) 53 and references cited therein. 5 I. Matsuda, M. Shibata, S. Sato and Y. Izumi, Tetrahedron Z.&t., 28 (1987) 3361. 6 S. J. Neeson and P. J. Stevenson Tetrahedron Lett., 29 (1988) 813. 7 A. R. Stein, R. D. Dawe and J. R. Sweeb, Can. J. Chem., 63 (1985) 3442. 8 G. Bourgeois end R. LaIande, Bull. Sot. Chim. Fr., (1972) 4324. 9 D. J. Brickwood, W. D. Ollis, J. S. Stephanotov and J. F. Stoddart, J. Chem. Sot., Perkin Trans. 1 (1978) 1398. 10 F. Sugawara, T. Sugiyama, A. Kobayaehi end K. Yemaehita, Agric. Bill. Chem., 42 (1978) 847. 11 See also P. Vioget, P. Vogel and R. RouIet, Angew. Chem. Suppl., (1982) 1128; P. Vioget, M. Bonivento, R. Roulet and P. Vogel, Helu. Chim. Acta, 67 (1984) 1638. 12 J. Wagner, E. Vieira and P. Vogel, Helv. Chim. Acta, 71 (1988) 624.