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A new method for preparing 1-phenylthio-1-trimethylsilylalkanes: the preparation of α-silylcarbanions and olefins.
Tetrahedron Letters, V01.22, No.X), PP Printed in Oreat Britain
2923 - 2926, 1981
0040-4039/81/302923~4$02 01981 Pergamon Press Ltd.
By DPVID J. Ar,FR
Department of Organic Chemistry, Robert Robinson Laboratories, p.o.8ox l47, Tiverpool, r,69 3FX. Summary: I-Phenylthio-l-trimethylsilylalkanes(1) are prepared in high yie'd from l,l-bis(phenylthio)acetals(2) by reaction vith lithium nanhthalenide(3) followed by chlorotrimethylsilane. cx-Silylcarbanion§ are formed from the alkanes(1) and lithium naphthalenide(3). Subsequent reaction vith cerbonyl compounds gave the olefins(4) via the Peterson reaction.
The ureparation of l-phenylthio-1-trimethylsilylalkanes(1) has been described previously1-3 . They are readily available from phenylthiotrimethylsilylmethane(2) by alkylation of the anion192 or Ly the addition of alkyllithiums to appropriately substituted olefins3 (scheme 1).
PhS/Si
Me
IfbuLi 3 2IRX
> PhS P
SiMep
(1 I
Scheme 1
IIR’LVTMEDA Et20/00C
AsPh SiMe3
X=CI
or SPh
In addition to the above methods, l-phenylthio-l-trimethylsilylalkanes may be prepared from bis(phenylthio)acetals(Z) by the method of Screttas4 and Cohen5 . The acetal(2) was odded to a solution of lithium naphtholenide(Ti Naph)(3)(2.2 equivalents) at -7S°C and stirred at this
temperature
for p.25h.. Quenching the reaction with
chlorotrimethylsil?ne pave, after vork-un, the alkane(l)(see table 1 and scheme 2). As bis(ohenylthio)acetals(2) can be prepared from aldehydes and thiophenol in the presence of an acid6 , besides alkylation of bis(nhenylthio)methane7, the above reaction formally describes the use of I-phenylthio-l-trimethylsilylalkanes(1~as an aldehyde protecting You?
because these allCanes
have already been converted to their
2923
2924
corresponding aldehydes 192 . Although this is feasible, the reaction's main use is to provide a new, high yielding method for preparing the al_kanes(l)
PhS-SPh
when the R group
-1
is not a straight alkyl chain.
fbuLi 2)RXz-----,
PhS
RCHO -w-----~~~~‘~ Scheme 2 Unlike the Wittig reaction8, the Peterson reaction' has not 10 found such a widespread use to prepare olefins . One of the reasons for this is the oc-silylcarbanions are not readily available. Ot-Silylcarbanions have been prepared by the addition of alkyllithiums to 11 , substitution of selenium 12 or directly from the silane 13 , vinylsilanes although this last method gives low yields. The major class of d-silylcarbanion
has another anion stabilising
group present Ir, but
15 . The reaction of these, of course, giv- rise to substituted olefins l-phenylthio-1-trimethylsilylalkanes(1)
with lithium naphthalenide(3)
is, therfore, a useful general method for preparing ti-silylcarbanions. 17 to give, via the Peterson reaction9, the corresponding olefins(&)(see table 2 and
These anions were reacted with aldehydes or ketones
scheme 3)
SiMe3
PhS (1 I
Li Naph THF
’
Li’Si
Me R’R2co’ 3
-7 8°C Scheme 3
This method of preparing olefins is novel as l-phenylthio-l-trimethylsilylalkanes(1) are masked aldehydes 192 and retrosynthetically the olefin is formed by joining two carbonyl groups together:-
2925
TABLE 1 The preparation
of l-uhenylthio-l-trimethylsilylalkanes(1)
bis(phenylthio)acetals followed
from
by reaction with lithium naphthalenide
by chlorotrimethylsilane. Yield of (l)(S)
(2) ,R=
86
R
G:
90 82
iPr
87
%.l
75
%u
79
y5%
72 sq
Ph
TABI,F:2 The ureparation
of olefins from l-phenylthio-l-trimethylsilylalkanes(1)
by reaction with lithium naphthalenide
followed by the carbonyl
compound. Yield of olefin(&)(%) (l),R= c:
nPrCHC
PhCOVe
Ph2CO
PhcFfO
Ve2CC
a
64
77
-
83
71
82
78 74
75 86
-61
76 79
so
"1
85
76
7c
69
%CRC
H
74 Ph16
59
Pcknowledgements. The author wishes of Southampton), Professor
to thank Professor R.C. Cookson rRS (University
Dr. Tan mleming
T-0. Sutherland
(University of Cambridge)
and
(Universjty of Liverpool) for their
interest and encouragement.
References
and Fotes.
l)D.J. Ager and S.C. Cookson, Tetrahedron 2)P.J. Kocienski, Tetrahedron
Ietters, 198C,2&1677.
T.etters, lS@C,~,l559.
2926
3)D.J.
Ager, Tetrah8dron
Letters, 1981,22,587.
4)C.G. Screttas and v. XichaScrettas,
J.Org.Chem.,1979,&713.
5)T. Cohen, Id.". Dani8wski and R.B. Weisenfeld,
Tetrahedron Letters,
1978,4665; T. Cohen, R.E. Gapinski and R. Hutchins, J.Org.Chem., 1979,4&3599 44,3&l.
and T-Cohen and R.B. Weisenfeld,
J.Org.Chem., 1979,
See also T. Cohen and J.R. ?htz, Synth.Comaun.,
6)J.F. Arens, M. Froling and 4. Froling, Rec.Trav.chim., and A. Froling and J.F. Arens, Rec.Trav.chim.,
198o,l@,311.
1959,78,663
1962,8&1009.
7)E.J. Corey and D. Seebach, J.OrP.Chem., 1966,21,4097. 8)G. Wittig and G. Geissler, Annalen,
1953,=,44.
9)D.J. Peterson, [email protected]., 1968,3,?R0. lC1)The exception is anions derived from trimethglsilylmethyl
chloride,
which is commercially available. See a)D.J. Peterson, llfganometallic Chem.Rev.(Al, Tetrahedron
1972,1,358 and b)T.A. Chan, F. Chang and F. Vi&ur
T,etters, lQ70,1137.
1l)a)A.G. Brook, J.74. Duff and D.G. Anderson, Canad.J.Chem.,
1970,&8,561
b)P.F. Audrlik and D. Peterson, Tetrahedron Letters, lQ74.1133. 12)W. Dumont and A. Krief, Angew.Chem.Tnt.Ed., 13)D.J. Peterson, J.Organometallic U)The
1976,x,161.
Chem., 1967,&373.
use of one or more phenyl groups or a second silyl group hPs
been included in this group. 15)For examples of groups used seo a)H. Sakurai, K.-i. Nishiwaka and v. Kira, Tetrahedron Letters, 1973,4193, b)I. Ojima and M. Kumagai, Tetrahedron
Iletters, 1974,4005, c)K. Sachdev and R.S. Sachdev,
Tetrahedron
Letters, 1976,4223, d)K. Sachdev, Tetrahedron
T,etters,
1976,4041, e)P. Shimoji, H. Taguchi, K. nshima, H. Yamamoto and A. Rozaki, J.Amer.Chem.Soc.,
1974,96,1620, f)F. Cooke
J.Chem.Soc..Chen.Commun.,1977,513, J.pr~.Chem.,
1972,2,939,
h)P.*. Carey and 0. Fernandes, J.crg.Chem.,
1='73,.38,267G,and referemes
I, 2, 9, lob, lla and 16.
16)D.J. Ager, Tetrahedron T,etters, 1980,2l,4759. 17)Other electrophiles are under active investigation.
(Received in UK 71 May 17Sl)
nd P. yagnus,
g)F.b. Carey and A.S. Court,
2923 - 2926, 1981
0040-4039/81/302923~4$02 01981 Pergamon Press Ltd.
By DPVID J. Ar,FR
Department of Organic Chemistry, Robert Robinson Laboratories, p.o.8ox l47, Tiverpool, r,69 3FX. Summary: I-Phenylthio-l-trimethylsilylalkanes(1) are prepared in high yie'd from l,l-bis(phenylthio)acetals(2) by reaction vith lithium nanhthalenide(3) followed by chlorotrimethylsilane. cx-Silylcarbanion§ are formed from the alkanes(1) and lithium naphthalenide(3). Subsequent reaction vith cerbonyl compounds gave the olefins(4) via the Peterson reaction.
The ureparation of l-phenylthio-1-trimethylsilylalkanes(1) has been described previously1-3 . They are readily available from phenylthiotrimethylsilylmethane(2) by alkylation of the anion192 or Ly the addition of alkyllithiums to appropriately substituted olefins3 (scheme 1).
PhS/Si
Me
IfbuLi 3 2IRX
> PhS P
SiMep
(1 I
Scheme 1
IIR’LVTMEDA Et20/00C
AsPh SiMe3
X=CI
or SPh
In addition to the above methods, l-phenylthio-l-trimethylsilylalkanes may be prepared from bis(phenylthio)acetals(Z) by the method of Screttas4 and Cohen5 . The acetal(2) was odded to a solution of lithium naphtholenide(Ti Naph)(3)(2.2 equivalents) at -7S°C and stirred at this
temperature
for p.25h.. Quenching the reaction with
chlorotrimethylsil?ne pave, after vork-un, the alkane(l)(see table 1 and scheme 2). As bis(ohenylthio)acetals(2) can be prepared from aldehydes and thiophenol in the presence of an acid6 , besides alkylation of bis(nhenylthio)methane7, the above reaction formally describes the use of I-phenylthio-l-trimethylsilylalkanes(1~as an aldehyde protecting You?
because these allCanes
have already been converted to their
2923
2924
corresponding aldehydes 192 . Although this is feasible, the reaction's main use is to provide a new, high yielding method for preparing the al_kanes(l)
PhS-SPh
when the R group
-1
is not a straight alkyl chain.
fbuLi 2)RXz-----,
PhS
RCHO -w-----~~~~‘~ Scheme 2 Unlike the Wittig reaction8, the Peterson reaction' has not 10 found such a widespread use to prepare olefins . One of the reasons for this is the oc-silylcarbanions are not readily available. Ot-Silylcarbanions have been prepared by the addition of alkyllithiums to 11 , substitution of selenium 12 or directly from the silane 13 , vinylsilanes although this last method gives low yields. The major class of d-silylcarbanion
has another anion stabilising
group present Ir, but
15 . The reaction of these, of course, giv- rise to substituted olefins l-phenylthio-1-trimethylsilylalkanes(1)
with lithium naphthalenide(3)
is, therfore, a useful general method for preparing ti-silylcarbanions. 17 to give, via the Peterson reaction9, the corresponding olefins(&)(see table 2 and
These anions were reacted with aldehydes or ketones
scheme 3)
SiMe3
PhS (1 I
Li Naph THF
’
Li’Si
Me R’R2co’ 3
-7 8°C Scheme 3
This method of preparing olefins is novel as l-phenylthio-l-trimethylsilylalkanes(1) are masked aldehydes 192 and retrosynthetically the olefin is formed by joining two carbonyl groups together:-
2925
TABLE 1 The preparation
of l-uhenylthio-l-trimethylsilylalkanes(1)
bis(phenylthio)acetals followed
from
by reaction with lithium naphthalenide
by chlorotrimethylsilane. Yield of (l)(S)
(2) ,R=
86
R
G:
90 82
iPr
87
%.l
75
%u
79
y5%
72 sq
Ph
TABI,F:2 The ureparation
of olefins from l-phenylthio-l-trimethylsilylalkanes(1)
by reaction with lithium naphthalenide
followed by the carbonyl
compound. Yield of olefin(&)(%) (l),R= c:
nPrCHC
PhCOVe
Ph2CO
PhcFfO
Ve2CC
a
64
77
-
83
71
82
78 74
75 86
-61
76 79
so
"1
85
76
7c
69
%CRC
H
74 Ph16
59
Pcknowledgements. The author wishes of Southampton), Professor
to thank Professor R.C. Cookson rRS (University
Dr. Tan mleming
T-0. Sutherland
(University of Cambridge)
and
(Universjty of Liverpool) for their
interest and encouragement.
References
and Fotes.
l)D.J. Ager and S.C. Cookson, Tetrahedron 2)P.J. Kocienski, Tetrahedron
Ietters, 198C,2&1677.
T.etters, lS@C,~,l559.
2926
3)D.J.
Ager, Tetrah8dron
Letters, 1981,22,587.
4)C.G. Screttas and v. XichaScrettas,
J.Org.Chem.,1979,&713.
5)T. Cohen, Id.". Dani8wski and R.B. Weisenfeld,
Tetrahedron Letters,
1978,4665; T. Cohen, R.E. Gapinski and R. Hutchins, J.Org.Chem., 1979,4&3599 44,3&l.
and T-Cohen and R.B. Weisenfeld,
J.Org.Chem., 1979,
See also T. Cohen and J.R. ?htz, Synth.Comaun.,
6)J.F. Arens, M. Froling and 4. Froling, Rec.Trav.chim., and A. Froling and J.F. Arens, Rec.Trav.chim.,
198o,l@,311.
1959,78,663
1962,8&1009.
7)E.J. Corey and D. Seebach, J.OrP.Chem., 1966,21,4097. 8)G. Wittig and G. Geissler, Annalen,
1953,=,44.
9)D.J. Peterson, [email protected]., 1968,3,?R0. lC1)The exception is anions derived from trimethglsilylmethyl
chloride,
which is commercially available. See a)D.J. Peterson, llfganometallic Chem.Rev.(Al, Tetrahedron
1972,1,358 and b)T.A. Chan, F. Chang and F. Vi&ur
T,etters, lQ70,1137.
1l)a)A.G. Brook, J.74. Duff and D.G. Anderson, Canad.J.Chem.,
1970,&8,561
b)P.F. Audrlik and D. Peterson, Tetrahedron Letters, lQ74.1133. 12)W. Dumont and A. Krief, Angew.Chem.Tnt.Ed., 13)D.J. Peterson, J.Organometallic U)The
1976,x,161.
Chem., 1967,&373.
use of one or more phenyl groups or a second silyl group hPs
been included in this group. 15)For examples of groups used seo a)H. Sakurai, K.-i. Nishiwaka and v. Kira, Tetrahedron Letters, 1973,4193, b)I. Ojima and M. Kumagai, Tetrahedron
Iletters, 1974,4005, c)K. Sachdev and R.S. Sachdev,
Tetrahedron
Letters, 1976,4223, d)K. Sachdev, Tetrahedron
T,etters,
1976,4041, e)P. Shimoji, H. Taguchi, K. nshima, H. Yamamoto and A. Rozaki, J.Amer.Chem.Soc.,
1974,96,1620, f)F. Cooke
J.Chem.Soc..Chen.Commun.,1977,513, J.pr~.Chem.,
1972,2,939,
h)P.*. Carey and 0. Fernandes, J.crg.Chem.,
1='73,.38,267G,and referemes
I, 2, 9, lob, lla and 16.
16)D.J. Ager, Tetrahedron T,etters, 1980,2l,4759. 17)Other electrophiles are under active investigation.
(Received in UK 71 May 17Sl)
nd P. yagnus,
g)F.b. Carey and A.S. Court,