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Reaction of trialkyl phosphites with phosphonodithioformates: Access to substituted methylene bis-phosphonates via stabilized ylids.
‘lhmh&mLataas
Vol.3l.No.8,p~ 1151-1154.1990
w4o-4o39h3os3.00+ .oo PeapmcmPressplc
RinkdiUGldBrinin
REACTION OF TRIALKYL PHOSPHITES WITH PHOSPHONODITHIOFORMATES: SUBSTITUTED METHYLENE BIS-PHOSPHONATES
VIA STABILIZED
ACCESS TO YLIDS.
Andrew Bulpin, Serge Masson* and Aboubacary Sene Laboratoire de Chimie des Compos&s Thioorganiques (associe au CNRS), Institut des Sciences de la Matiere et du Rayonnement (IsMRa), Universite , F 14032 CAEN, France.
Summary : The addition of 2 equivalents of trialhylphosphite to phosphonodithioformates leads to stabilized phosphonium yliak. The reaction of these yliak with hydrochloric acid, methyl iodide, benzyl-, allyl- andpropargyl- bromide is studied : C-Protonation or S-alkylation which occurs with an Arbuzov-type dealkylation gives access to substituted methylene bis-phosphonates or to stabilized sulphonium yliak Apart from the well known desulphurisation and coupling reactions of derivatives of 1,3-dithiole-2-thiones leading to tetrathiafulvalene derivatives (constituents of organic conductors)* and the Corey-Winter olefin synthesis from cyclic thionocarbonates2, the reactions of trialkylphosphites with thiocarbonyl compounds are not commonly used in organic synthesis. A few studies have shown that the regioselectivity of the initial thiophilic or carbophilic addition of the phosphite and the evolution of the assumed 1,3-dipolar intermediates depend on the nature of the substituents on the thiocarbonyl group. \o 0 ,c-s-P(OR&
The formation of alkenes or coupled products (from cyclic- 1.2 thionocarbonates and ttithiocarbonates2 ) and the generation of phosphonium ylids (from cyclic-l,3 trithiocarbonates 3, hexafluorothioacetone‘l, chlorothio- and dithio-formates thiophilic
and thiophosgene6) have been observed. All these reactions can be interpreted by an initial
addition.
cyclohexanethione7.
Phosphonates
resulting
from an initial
carbophilic
addition
are obtained
with
Furthermore, the reaction with thiobenzophenone8 leads to a complex mixture of products
whose formation has not yet been clearly rationalised. Deprotonation is also a possible reaction and a Claisen-type condensation occurs when a trialkylphosphite is added to an enethiolisable dithioester such as ethyl dithioacetateo. This paper points out the potential synthetic uses of the reaction of trialkylphosphites prepared phosphonodithioformates*o
with the easily
giving access to stabilized ylids. precursors of substituted methylene bis-
phosphonates, compounds of biological interest1 l. We found that the addition of the phosphonodithioformates (1-5) to two equivalents of trialkylphosphite in THF (Oat 2oOC) leads to the stabilized phosphonium ylids (6-10) via an assumed thiophilic addition followed by desulphurisation.
After evaporation of the solvent and trialkylthiophosphate,
these ylids. obtained in quasi
quantitative yield according to nmr spectra, were used without purification. The 31P NMR signals observed for the P-atoms of the phosphono and phosphonium groups in ylids 6-10 appear at the expected chemical shifts, ._. 28
1151
1152
and. 50 ppm12 respectively, with PP-coupling constants of 138 to 149 Hz. In the 13C NMR spectra, ,high field signals (dd N t), with large CP-coupling constants (- 220 Hz) are observed for the negatively charged sp2 ylid carbon atoms13 ( see table below). OS
2 (R’OIJ’
(RIO);-~-&
-
f (R’OI#-6-G
- (R’O)$S dithbformates
R’
1 2
3 4 5
OH
s
(Oti,,
0
[R’o&&-~
(OR’,, AR2
A9
3
YlldS
his-phosphonates
Ethyl 11
6 7
Methyl Crotyl
11 1,
3 9
Meth~thoxymethyl Dodecyl
11 12 13 14
Methyl
15
i-PI-Owl
+ Rkl
10
When solutions of the ylids (6-10) in methylene chloride at O’C were saturated with HCl gas 620 mn), the bis-phosphonates (11-15) were quantitatively formed via a protonation and an Arbuzov-type dealkylation (formally represented by the mechanism A).
B
A
R2 = F? = Methyl
16
R2 = Methyl, R’ = Benzyl
17
We did not observe any reaction between these stabilized phosphonium ylids and benzaldehyde in refluxing THP. However, these compounds were found to react with good alkylating reagents such as methyl iodide and benzyl-, allyl-, crotyl- and propargyl- bromide. Addition of methyl iodide or benzyl bromide (1.2 to 1.5 equiv.) to the ylid 6 in THP at O°C led to the stabilized sulphonium ylids 16 and 17 respectively in 90 and 82% yields (Scheme 2). As was observed for the analogous sulphoniuml4a and ammonium 14b ylids stabilized by two carbonyl or cyano groups, 16 and 17 are stable at room temperature and 16 can even be distilled at 14OY/O.OlTorr. The formation of 16 and 17 can be rationalised by an alkylation on the sulphur with an Arbuzov-type dealkylation of the phosphonium moiety (intermediate B, scheme 2). At this temperature, ethyl iodide, formed during the reaction, does not compete with the more reactive methyl iodide or benzyl bromide. Ethyl iodide was found to react with the phosphonium ylid 6 in refluxing toluene but under these conditions the principal product formed was the bis-phosphonate 11.Such a compound could result from the auto-protonation
of an initially formed, but thermally unstable, S-ethyl. S-methyl sulphonium ylid
(analogue of 16 and 17). with the simultaneous elimination of ethylene. This reaction, the so-called ci~limination is known to take place with S-ethyl, S-methyl sulphonium ylids stabilized by two carboxylate groupsl5. Addition of allyl, crotyl, and propargyl bromides (1.3 eq) to the ylid 6 in THP at 50°C for 24.48 and 150 h. respectively, led to the bis-phosphonates l&19,20
with yields around 75%. The structures of these allylic and
allenic methylene bis-phosphonate derivatives were deduced from their NMR spectrat6. The C-alkylation with “inversion” of the unsaturated chain can easily be explained by a [2,3] sigmatropic rearrangement of an allylic or propargylic
sulphonium
ylid C or D (initially formed by alkylation on the sulphur with the Arbuzov-type
dealkylation
of the alkoxyphosphonium
group). Indeed, such a rearrangement
is well-known for S-ally1 and
1153
S-propagyl substituted ylids and carbanions 15917.The bis-phosphonate 19 prepared from ylid 6 was also obtained by the addition of methyl iodide to the S-crotyl phosphonium ylid 7 and this is in good agreement with the formation of an S-crotyl, S-methyl sulphonium ylid C which could reasonably be assumed as common intermediate in both cases. However, a direct C-allylation
(or allenylation)
of 6 via a SN2’ mechanism (followed by the
phosphonium dealkylation) cannot be completly excludedtg.
SMe R’=Et
R=H R=Me
18 19 4
SMe 20
R’ = Et
Further studies concerning the stability and reactivity of these new stabilized ylids and substituted methylene bis-phosphonates are in progress. NMR CHARACTERISTICS OF NEW COMPOUNDS. Chemical shifts Qpm),
Coupling constants J(Hz)
Phosphonium ylids 8 9
sulphonium ylids 10
6
7*
28.50
27.40
51.09
50.7 1
51.77
51.20
48.25
‘JPA~
146.8 *solvent: CC4 +C&j
147.9
138.0
148.4
149.9
SCa (dd* t)
20.62
19.30
~JCPA*lJcPg
,Q220
-219
@A
(4
WJ (d)
3‘P NMR (C@6) 28.17 28.58
28.14
16
17
31P NMR (CDC13) SP (s) 25.60 25.64
13C NMR (CDC13)
13CNMR (C&) 17.57
19.64
22.85
&a (s)
24.45
22.95
**
+#220
d 220
‘JCP
203.0
203.7
* * 217.6 and 221.4 11
Methylene bis-phosphonates* 12 13 14
15
: (RIO)r$+.~“b
1H NMR (CDC13)
SR2
SHa (t)
2.86
3.07
3.05
3.02
2.76
2JHaP
22.0
22.0
22.0
22.0
22.0
3tP NMR (CDC13) (s)
17.58
18.11
&a (t).
37.61
35.04
‘JCaP
138.1
139.5
Sp
18.39
17.88
l3C NMR (CDCl3) 33.11 37.51 139.7
139.0
6 to 10
0
15.98
Ha 0
(RIO&+!
(Od,2 &
40.22 139.8
*ll has already been described (ref. 1Id) ; for NMR caracteristics of 18.19 and 20, see ref. 16
11to 15
1154
REFERENCES 1976, 489 and cited ref..b) Krief A., Termhedron,
1.
a) Narita M., Pittman Ch. II., Synfhesis, and cited ref..
1986, 42, 1209
2.
a) Corey E.J., Winter RAE., Ibid., 1965,87,934.
3.
Corey E.J., Mlfrkl G., Tetrahedron Len., 1967.33,
4.
Middleton
5.
a) Birum G.H., U.S. Patent, 1963.3089 CA.. 191056.
6.
Masson S., Sene A., kfutchinson
7.
Yoneda S., Kawase T., Yoshida Z.I., J. Org. Chem., 1978.43,
8.
Ogata Y., Yamashita
9.
Yoshida Z.I., Yomeda S., Kawase T., fnabu M., ‘I%frclhe&on Left., 1978, IS, 1285.
10.
Grisfey D.W., J. Org. Ckem., 1961, 26, 2544. 3lP NMR of the phosphonodithioformates: ext.f-13POq): 1: - 2.41. 2: - 2.74, 3: -3.27, 4: - 2.44, 5: - 4.25.
11.
a) Engcl II., CBem. Rev. 1977. 3, 349. 1~)I;r;mris M.D., Ccnmmr R.L., 1. C/rem. IStfrrc., 1078, 55, 760. c) Hutchinson D.W., Anrivirul Reseurch, 10X5, 5, lY3. d) Ollivicr I<., Sturtz G., Legendre J.M., Jacolot G., Turzo A., Eur. J. Med. Chem.-Chim. 7Itcr.. 1916, 21, 103 aad cited ref..
12.
Burgada
13
a) Gray G.A., J. Am. C/rem. Sot., 1973, 95, 7736. b) Bottin-Strzafko T., Seyden-Penne’ J., Pouet M.J., Simmonnin M.P.. J. Org. Chem., 1978, 43, 4346. c) Griffiths D.V., Tebby J.C.. J. Chem. Sot., Chem. Commun., 1986,87 I.
14.
a) Hochrainer A., Wessely F., Tefrahedron Lerr., 1965, 721; Cook A.F., Moffat J.G., .I. Am. C/tern. Sot., 1967, 90,740; Matsuyama Ii., Minato H., Kobayashi M., Bull. Chem. Sot. Jup. , 1973.46, 1512; Kral V. Arnold Z., Collecr.Czec/~.C/rem.. 1978.43, 124X. b) Gross H., Costisella B., Jortrnnlf.Prak?.Chemie, 1986, 328, 231; Kofehmainen E., Lnatikainen R., Rissanen K., Valkonen J., Saman D., Krnl V., J. Chem. Sot., Perkin Trunr II, 1989,859, and cited ref..
15.
Ando W., Accounts of Chemical Research, 1977, IO, 179, and cited ref..
16.
NMR characteristics: 111 NMR (6, int.TMS): IX (CDCl3) : 2.4 (s, SCf13); 2.4 to 3.2(m, -C&-CH=); 4.9 to 5.3 (m, CHz=); 5.6 to 6.5 (m. -CM=); 19 (C#c,) : 1.7 (d, 3Jttll= 6,5, C_&CfQ 2.5 (,., s. SCH3 ); 2.6 lo 3.5 6.4 to 7. I (in, Cl la=Cj_f_) ; 20 (CUCl3) : 2.3 (s, SC1 13) ; 4.8 lo (m, CIf3-CH ); 4.9 to 5.3 (m, C&=C);
J. Am. Chem. Sot., 1963, X5, 2677. b) Corey E.J., Carey F.A.. Winter A.E.,
3201.
W.J., Sharkey W.H., J. Org. Chem., 1965,30, 891
; C.A., 11 562 h. b) Birum G.H., U.S. Patent, 1978,4 071 584 ;
D.W., Thornlon
D.M., Phosphorxc nndsul/ur,
M., Mizutani M., Terrahedron,
R., f.,eroux Y., El Khoshneih
1384.
1988, 40. 1.
1980.
1974,3O, 3709.
(CDClj,
8,
Y.O., ‘ILfm/rc*&on Izerr., 1980, 21, 925.
i.l(m, cH2=) ; 5.3 to 5.8 (m&f=) ; 13C NMR (6, TMS): 18 (CDC13) : 14.3 (,., s, SCH3); 36.6 (1. 2Jcp =3.9, cH2-CFf=); 46.8 (t, *Jcp = 136.4, c-SMe); 117.6 (s, -CH=) 132.8 (1. 3Jcp = 6.6, CH2=); 19 (CDCl3) : 15.2 (d s, SCH3) ; 18.8 (t, 3Jcp = 4.3, cH3-CH) ; 43.0 (s, CH&H) : 52.0 (t. ‘Jcp=l33.5, c-SMe ); 115.1 (s, CIfz=) ; 140.3 (t. 3Jcp = 5.1, XII=); 20 (CDCf3) 14.8 ( _ s, SCI-13); 47.5 (t, IJcp =141.5, c-SMe); 79.6 (t. 4Jcp = 2.8, =CIlz); 86.9 (t. 2Jcp = 8.1, -CH=); 210.4 (1, 3Jcp = 10.9, =C=) ; 3fP NMR (CDCl3.6, ext. H3pO4): 18: lY.94; 19: 19.81; 20: 16.84. 17.
a) Julia S., Huynh C., Michelot C., Terrahnfrcm Lerr., 1972.34. 3587; b) Grieco PA., Meyers M., Finkellor R.S., J. OrR. Chem.. 1974, 39, 1 I9 ; c) Iqcr I... S:quct M., ‘I’huillicr A., Juli:l S.. J. Or.qtrnomrrtr/. C/wm., 1Y75, 96, 3 13 ; d) OISSOIILA., Ac~tr. C/rem. .Sar,~tf., 1977, II 3 I, 639.
18.
For the alkylation of selenium-stabilized enolates, a direct SN~’ alkylation, favourised by secondary orbital interactions between the carbon-halogen component of the ally1 halide LUMO and the heteroatom component of the enolate HOMO, was proposed as an alternative to the sulphonium ylid-sigmatropy mechanismlg. However, according to the authors, since sulphur lone pairs generally exhibit higher ionization Potentials than their corresponding selenium analogues, it follows that sulphur-stabilized enolates (or ylids in our case) will participate less readily in an SN~’ mechnnisin.
19. (Received
Solomon M., Hoekstra W., Zima G., Liotta D., J. Org. Chcm., 1988,53, in France 25 October 1989)
5058.
Vol.3l.No.8,p~ 1151-1154.1990
w4o-4o39h3os3.00+ .oo PeapmcmPressplc
RinkdiUGldBrinin
REACTION OF TRIALKYL PHOSPHITES WITH PHOSPHONODITHIOFORMATES: SUBSTITUTED METHYLENE BIS-PHOSPHONATES
VIA STABILIZED
ACCESS TO YLIDS.
Andrew Bulpin, Serge Masson* and Aboubacary Sene Laboratoire de Chimie des Compos&s Thioorganiques (associe au CNRS), Institut des Sciences de la Matiere et du Rayonnement (IsMRa), Universite , F 14032 CAEN, France.
Summary : The addition of 2 equivalents of trialhylphosphite to phosphonodithioformates leads to stabilized phosphonium yliak. The reaction of these yliak with hydrochloric acid, methyl iodide, benzyl-, allyl- andpropargyl- bromide is studied : C-Protonation or S-alkylation which occurs with an Arbuzov-type dealkylation gives access to substituted methylene bis-phosphonates or to stabilized sulphonium yliak Apart from the well known desulphurisation and coupling reactions of derivatives of 1,3-dithiole-2-thiones leading to tetrathiafulvalene derivatives (constituents of organic conductors)* and the Corey-Winter olefin synthesis from cyclic thionocarbonates2, the reactions of trialkylphosphites with thiocarbonyl compounds are not commonly used in organic synthesis. A few studies have shown that the regioselectivity of the initial thiophilic or carbophilic addition of the phosphite and the evolution of the assumed 1,3-dipolar intermediates depend on the nature of the substituents on the thiocarbonyl group. \o 0 ,c-s-P(OR&
The formation of alkenes or coupled products (from cyclic- 1.2 thionocarbonates and ttithiocarbonates2 ) and the generation of phosphonium ylids (from cyclic-l,3 trithiocarbonates 3, hexafluorothioacetone‘l, chlorothio- and dithio-formates thiophilic
and thiophosgene6) have been observed. All these reactions can be interpreted by an initial
addition.
cyclohexanethione7.
Phosphonates
resulting
from an initial
carbophilic
addition
are obtained
with
Furthermore, the reaction with thiobenzophenone8 leads to a complex mixture of products
whose formation has not yet been clearly rationalised. Deprotonation is also a possible reaction and a Claisen-type condensation occurs when a trialkylphosphite is added to an enethiolisable dithioester such as ethyl dithioacetateo. This paper points out the potential synthetic uses of the reaction of trialkylphosphites prepared phosphonodithioformates*o
with the easily
giving access to stabilized ylids. precursors of substituted methylene bis-
phosphonates, compounds of biological interest1 l. We found that the addition of the phosphonodithioformates (1-5) to two equivalents of trialkylphosphite in THF (Oat 2oOC) leads to the stabilized phosphonium ylids (6-10) via an assumed thiophilic addition followed by desulphurisation.
After evaporation of the solvent and trialkylthiophosphate,
these ylids. obtained in quasi
quantitative yield according to nmr spectra, were used without purification. The 31P NMR signals observed for the P-atoms of the phosphono and phosphonium groups in ylids 6-10 appear at the expected chemical shifts, ._. 28
1151
1152
and. 50 ppm12 respectively, with PP-coupling constants of 138 to 149 Hz. In the 13C NMR spectra, ,high field signals (dd N t), with large CP-coupling constants (- 220 Hz) are observed for the negatively charged sp2 ylid carbon atoms13 ( see table below). OS
2 (R’OIJ’
(RIO);-~-&
-
f (R’OI#-6-G
- (R’O)$S dithbformates
R’
1 2
3 4 5
OH
s
(Oti,,
0
[R’o&&-~
(OR’,, AR2
A9
3
YlldS
his-phosphonates
Ethyl 11
6 7
Methyl Crotyl
11 1,
3 9
Meth~thoxymethyl Dodecyl
11 12 13 14
Methyl
15
i-PI-Owl
+ Rkl
10
When solutions of the ylids (6-10) in methylene chloride at O’C were saturated with HCl gas 620 mn), the bis-phosphonates (11-15) were quantitatively formed via a protonation and an Arbuzov-type dealkylation (formally represented by the mechanism A).
B
A
R2 = F? = Methyl
16
R2 = Methyl, R’ = Benzyl
17
We did not observe any reaction between these stabilized phosphonium ylids and benzaldehyde in refluxing THP. However, these compounds were found to react with good alkylating reagents such as methyl iodide and benzyl-, allyl-, crotyl- and propargyl- bromide. Addition of methyl iodide or benzyl bromide (1.2 to 1.5 equiv.) to the ylid 6 in THP at O°C led to the stabilized sulphonium ylids 16 and 17 respectively in 90 and 82% yields (Scheme 2). As was observed for the analogous sulphoniuml4a and ammonium 14b ylids stabilized by two carbonyl or cyano groups, 16 and 17 are stable at room temperature and 16 can even be distilled at 14OY/O.OlTorr. The formation of 16 and 17 can be rationalised by an alkylation on the sulphur with an Arbuzov-type dealkylation of the phosphonium moiety (intermediate B, scheme 2). At this temperature, ethyl iodide, formed during the reaction, does not compete with the more reactive methyl iodide or benzyl bromide. Ethyl iodide was found to react with the phosphonium ylid 6 in refluxing toluene but under these conditions the principal product formed was the bis-phosphonate 11.Such a compound could result from the auto-protonation
of an initially formed, but thermally unstable, S-ethyl. S-methyl sulphonium ylid
(analogue of 16 and 17). with the simultaneous elimination of ethylene. This reaction, the so-called ci~limination is known to take place with S-ethyl, S-methyl sulphonium ylids stabilized by two carboxylate groupsl5. Addition of allyl, crotyl, and propargyl bromides (1.3 eq) to the ylid 6 in THP at 50°C for 24.48 and 150 h. respectively, led to the bis-phosphonates l&19,20
with yields around 75%. The structures of these allylic and
allenic methylene bis-phosphonate derivatives were deduced from their NMR spectrat6. The C-alkylation with “inversion” of the unsaturated chain can easily be explained by a [2,3] sigmatropic rearrangement of an allylic or propargylic
sulphonium
ylid C or D (initially formed by alkylation on the sulphur with the Arbuzov-type
dealkylation
of the alkoxyphosphonium
group). Indeed, such a rearrangement
is well-known for S-ally1 and
1153
S-propagyl substituted ylids and carbanions 15917.The bis-phosphonate 19 prepared from ylid 6 was also obtained by the addition of methyl iodide to the S-crotyl phosphonium ylid 7 and this is in good agreement with the formation of an S-crotyl, S-methyl sulphonium ylid C which could reasonably be assumed as common intermediate in both cases. However, a direct C-allylation
(or allenylation)
of 6 via a SN2’ mechanism (followed by the
phosphonium dealkylation) cannot be completly excludedtg.
SMe R’=Et
R=H R=Me
18 19 4
SMe 20
R’ = Et
Further studies concerning the stability and reactivity of these new stabilized ylids and substituted methylene bis-phosphonates are in progress. NMR CHARACTERISTICS OF NEW COMPOUNDS. Chemical shifts Qpm),
Coupling constants J(Hz)
Phosphonium ylids 8 9
sulphonium ylids 10
6
7*
28.50
27.40
51.09
50.7 1
51.77
51.20
48.25
‘JPA~
146.8 *solvent: CC4 +C&j
147.9
138.0
148.4
149.9
SCa (dd* t)
20.62
19.30
~JCPA*lJcPg
,Q220
-219
@A
(4
WJ (d)
3‘P NMR (C@6) 28.17 28.58
28.14
16
17
31P NMR (CDC13) SP (s) 25.60 25.64
13C NMR (CDC13)
13CNMR (C&) 17.57
19.64
22.85
&a (s)
24.45
22.95
**
+#220
d 220
‘JCP
203.0
203.7
* * 217.6 and 221.4 11
Methylene bis-phosphonates* 12 13 14
15
: (RIO)r$+.~“b
1H NMR (CDC13)
SR2
SHa (t)
2.86
3.07
3.05
3.02
2.76
2JHaP
22.0
22.0
22.0
22.0
22.0
3tP NMR (CDC13) (s)
17.58
18.11
&a (t).
37.61
35.04
‘JCaP
138.1
139.5
Sp
18.39
17.88
l3C NMR (CDCl3) 33.11 37.51 139.7
139.0
6 to 10
0
15.98
Ha 0
(RIO&+!
(Od,2 &
40.22 139.8
*ll has already been described (ref. 1Id) ; for NMR caracteristics of 18.19 and 20, see ref. 16
11to 15
1154
REFERENCES 1976, 489 and cited ref..b) Krief A., Termhedron,
1.
a) Narita M., Pittman Ch. II., Synfhesis, and cited ref..
1986, 42, 1209
2.
a) Corey E.J., Winter RAE., Ibid., 1965,87,934.
3.
Corey E.J., Mlfrkl G., Tetrahedron Len., 1967.33,
4.
Middleton
5.
a) Birum G.H., U.S. Patent, 1963.3089 CA.. 191056.
6.
Masson S., Sene A., kfutchinson
7.
Yoneda S., Kawase T., Yoshida Z.I., J. Org. Chem., 1978.43,
8.
Ogata Y., Yamashita
9.
Yoshida Z.I., Yomeda S., Kawase T., fnabu M., ‘I%frclhe&on Left., 1978, IS, 1285.
10.
Grisfey D.W., J. Org. Ckem., 1961, 26, 2544. 3lP NMR of the phosphonodithioformates: ext.f-13POq): 1: - 2.41. 2: - 2.74, 3: -3.27, 4: - 2.44, 5: - 4.25.
11.
a) Engcl II., CBem. Rev. 1977. 3, 349. 1~)I;r;mris M.D., Ccnmmr R.L., 1. C/rem. IStfrrc., 1078, 55, 760. c) Hutchinson D.W., Anrivirul Reseurch, 10X5, 5, lY3. d) Ollivicr I<., Sturtz G., Legendre J.M., Jacolot G., Turzo A., Eur. J. Med. Chem.-Chim. 7Itcr.. 1916, 21, 103 aad cited ref..
12.
Burgada
13
a) Gray G.A., J. Am. C/rem. Sot., 1973, 95, 7736. b) Bottin-Strzafko T., Seyden-Penne’ J., Pouet M.J., Simmonnin M.P.. J. Org. Chem., 1978, 43, 4346. c) Griffiths D.V., Tebby J.C.. J. Chem. Sot., Chem. Commun., 1986,87 I.
14.
a) Hochrainer A., Wessely F., Tefrahedron Lerr., 1965, 721; Cook A.F., Moffat J.G., .I. Am. C/tern. Sot., 1967, 90,740; Matsuyama Ii., Minato H., Kobayashi M., Bull. Chem. Sot. Jup. , 1973.46, 1512; Kral V. Arnold Z., Collecr.Czec/~.C/rem.. 1978.43, 124X. b) Gross H., Costisella B., Jortrnnlf.Prak?.Chemie, 1986, 328, 231; Kofehmainen E., Lnatikainen R., Rissanen K., Valkonen J., Saman D., Krnl V., J. Chem. Sot., Perkin Trunr II, 1989,859, and cited ref..
15.
Ando W., Accounts of Chemical Research, 1977, IO, 179, and cited ref..
16.
NMR characteristics: 111 NMR (6, int.TMS): IX (CDCl3) : 2.4 (s, SCf13); 2.4 to 3.2(m, -C&-CH=); 4.9 to 5.3 (m, CHz=); 5.6 to 6.5 (m. -CM=); 19 (C#c,) : 1.7 (d, 3Jttll= 6,5, C_&CfQ 2.5 (,., s. SCH3 ); 2.6 lo 3.5 6.4 to 7. I (in, Cl la=Cj_f_) ; 20 (CUCl3) : 2.3 (s, SC1 13) ; 4.8 lo (m, CIf3-CH ); 4.9 to 5.3 (m, C&=C);
J. Am. Chem. Sot., 1963, X5, 2677. b) Corey E.J., Carey F.A.. Winter A.E.,
3201.
W.J., Sharkey W.H., J. Org. Chem., 1965,30, 891
; C.A., 11 562 h. b) Birum G.H., U.S. Patent, 1978,4 071 584 ;
D.W., Thornlon
D.M., Phosphorxc nndsul/ur,
M., Mizutani M., Terrahedron,
R., f.,eroux Y., El Khoshneih
1384.
1988, 40. 1.
1980.
1974,3O, 3709.
(CDClj,
8,
Y.O., ‘ILfm/rc*&on Izerr., 1980, 21, 925.
i.l(m, cH2=) ; 5.3 to 5.8 (m&f=) ; 13C NMR (6, TMS): 18 (CDC13) : 14.3 (,., s, SCH3); 36.6 (1. 2Jcp =3.9, cH2-CFf=); 46.8 (t, *Jcp = 136.4, c-SMe); 117.6 (s, -CH=) 132.8 (1. 3Jcp = 6.6, CH2=); 19 (CDCl3) : 15.2 (d s, SCH3) ; 18.8 (t, 3Jcp = 4.3, cH3-CH) ; 43.0 (s, CH&H) : 52.0 (t. ‘Jcp=l33.5, c-SMe ); 115.1 (s, CIfz=) ; 140.3 (t. 3Jcp = 5.1, XII=); 20 (CDCf3) 14.8 ( _ s, SCI-13); 47.5 (t, IJcp =141.5, c-SMe); 79.6 (t. 4Jcp = 2.8, =CIlz); 86.9 (t. 2Jcp = 8.1, -CH=); 210.4 (1, 3Jcp = 10.9, =C=) ; 3fP NMR (CDCl3.6, ext. H3pO4): 18: lY.94; 19: 19.81; 20: 16.84. 17.
a) Julia S., Huynh C., Michelot C., Terrahnfrcm Lerr., 1972.34. 3587; b) Grieco PA., Meyers M., Finkellor R.S., J. OrR. Chem.. 1974, 39, 1 I9 ; c) Iqcr I... S:quct M., ‘I’huillicr A., Juli:l S.. J. Or.qtrnomrrtr/. C/wm., 1Y75, 96, 3 13 ; d) OISSOIILA., Ac~tr. C/rem. .Sar,~tf., 1977, II 3 I, 639.
18.
For the alkylation of selenium-stabilized enolates, a direct SN~’ alkylation, favourised by secondary orbital interactions between the carbon-halogen component of the ally1 halide LUMO and the heteroatom component of the enolate HOMO, was proposed as an alternative to the sulphonium ylid-sigmatropy mechanismlg. However, according to the authors, since sulphur lone pairs generally exhibit higher ionization Potentials than their corresponding selenium analogues, it follows that sulphur-stabilized enolates (or ylids in our case) will participate less readily in an SN~’ mechnnisin.
19. (Received
Solomon M., Hoekstra W., Zima G., Liotta D., J. Org. Chcm., 1988,53, in France 25 October 1989)
5058.