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Convenient preparation of acyltrimethylsilanes from carboxylic acid derivatives
Tetrahedron Letters,Vol.28,No.28,pp Printed in Great Britain
CONVENIENT
PREPARATION
Jahyo Kang*,
OF ACYLTRIMETHYLSILANES
Jae Hyoung
oo40-4039/87 $3.00 + .Oo Pergamon Journals Ltd.
3261-3262,1987
FROM CARBOXYLIC
ACID DERIVATIVES
Lee, Koan Seong Kim, Jae Uk Jeong and Chongsuh
Department
of Chemistry,
Mapoku,
Seoul
Pyun
Sogang University 121, KOREA
Summary : Acylsilanes are prepared in good yields by the reaction of acid chlorides (or anhydrides) with LiAl(SiMe3)4 or LiMeAl(SiMe3)3 in the presence of a catalytic amount of CuCN.
Acylsilanes
are interesting
For some applications carboxylic
class of compounds
of this functionality,
acids was needed
which
undergo
a facile method
of reactions.
for acylsilanes
directly
l-3
from
in literature 4 a number of preparatively useful methods, most of which utilize acyl anion equivalents , due to the difficulty associated with generation of silyl anions under mild conditions. 596 Since trimethylsilyl
in our laboratories
a variety
anion is usually
thought
to be inappropriate
readily
available
especially
Al-Si reagents,
cause of the low ionic character independently A1(SiMe3)3 ponding
especially
in the presence
1).
verted
in LiAl(SiMe3)4
was transferred
that even functionalized
Furthermore,
addition
presumably
silylation
reactions
the available
amounts.
conducted
trimethylsilyl Notably,
The following
(0.036 g, 0.40 mmol) LiA1(SiMe3)4 0.5 h. solution
methyl
tion of aqueous
acylsilane
(4.0 mmol).
to methyl
carbamoyl
The mixture
of methyllithium
rate
ketones
chlorides,
was warmed
The usual work-up
esters,
to the hitherto
nitriles
useless
For those reactions
3261
= 2)
in any significant
is representative.
To CuCN
27.6 mL of 0.145 M solution it was stirred
with stirring
to O'C, and quenched
was added at O'C to a stirred
for the
number of
(RCOC1/Al(SiMe3)3*LiMe
up to O°C, where
followed
with Al(SiMe3)3,
for
addi-
gave 1.63 g
an equimolar
of Al(SiMe3)3
of
to the black
by dropwise
by Si02 chromatography
solution
con-
(Entry 12).
was not observed
was warmed
(Table
That the
that, due to the smaller
(1.35 g, 10.0 mmol) was added dropwise
acid.
useful
were individually
ate complex, which was also effective except
to
trimethylsilyl
(Entries 4 and 10).
can be utilized
for hexanoyltrimethylsilane
After 2 h, the mixture
sulfuric
anhydrides
groups, more LiMeAl(SiMe 3 ) 3 reagent transfer
of the corres-
to be more satisfactory,
amount of methyllithium
fashion
treated
the tricoordinated
quantity
at a synthetically
yields
itself,
acid chlorides
were
the be-
mole ratio of acid chloride
and phthalic
in satisfactory
in a similar
(95 %) of hexanoyltrimethylsilane.8 solution
The optimal
the corresponding
procedure
chloride
at -78'C.
Generally,
proved
in 33 mL THF at -78'C was added dropwise
in ether
Hexanoyl
conditions:
, It was
to be attractive
acid chlorides
of only a minute
7.
In this regard,
seemed
Consequently,
LiAl(SiMe3)4
benzoic
of an equivalent
provided
acid derivatives.
to acid chloride
acylsilanes
basic conditions
that only part of the four available
could also be silylated;
Al(SiMe3)3
formation
of CuCN (10 mole W).
system was inert to ketones,
etc. suggests
was needed.
under various with
the ate complex,
to the corresponding
present
of the Al-Si bond.
was close to 2.5, implying
Anhydrides
under strongly
Al(SiMe 3 ) 3 and LiAl(SiMe3)47,
reactions
whereas
generated
for carboxylic
the above reagents
acylsilane,
LiAl(SiMe3)4 groups
with
gave incomplete
even though there are available
ether
in pentane-THF
3262
(The pentane
was a solvent
CuCN (0.1 molar Stirring
equiv.
for the aluminum
at O°C for 0.5 h furnished Table Starting Material
Entry
reagent.).
After stirring
at O°C for 0.5 h, solid
to the acid chloride
1.
to be added) was added under nitrogen 9 the active silylating agent.
Preparation
Reagentb
blanket.
of hcyltrimethylsilanesa
Mole Ratio'
Reaction Timed
Yielde
Product
1
n-C5HllCOC1
2.5
2h
95 %
n-C5HllCOSiMe3
2
PhCOCl 1,
2.5
1.5
93
PhCOSiMe3
2.0
2
73
3 4
(PhC0)20
2.5
1.5
88
5
PhCH2COC1
2.5
1.5
89
2.5
1.5
90
A
2.5
1.75
89
A
2.5
1.75
89
A
2.5
2.5
86
A
2.5
1.5
81
B
2.0
2
90
B
2.0
2
52
6
II
PhCH2COSiMe3
CH2COSiMe3
CH2COC1 t-BuCOCl
10 11
t-BuCOSiMe
D-
3
COSiMe3
AcOCH2COSiMe3
COCl
5J 0
12
CN/
' Mole ratio of a See text for reaction condition. b A, LiAl(SiMe ) ; B, LiMeAl(SiMe ) acid derivative to the reagent. d At -78OC. e Bazei on the amount o 2 zcid derivative used
.
References Act. Chem. Res., 7, 77(1974).
1.
A.G. Brook, Adv. Organomet.
2.
b) H.J. Reich, a) D. Schinzer and C.H. Heathcock, Tetrahedron Lett., 2, 1881(1981). c) J. Enda and I. M.J. Kelly, R.E. Olson and R.C. Holtan, Tetrahedron, 2, 949(1983). d) H.J. Reich and E.K. Eisenhart, J. Org. Kuwajima, 3. Am. Chem. Sot., 107, 5495(1985). Chem. , 49, 5282(1984).
3.
a) M.E. Scheller and B. Frei, Helv. Chim. Acta, 67, Swenton, J. Org. Chem., 47, 2668(1982).
4.
For most recent one; T. Mandai, 11. Yamaguchi, Y. Nakayama, J. Otera and M. Kawada, hedron Lett., 6, 2675(1985); T. Aoyama and T. Shioiri, ibid, 7, 2005(1986).
5.
a) D.C. Davis, Organomet. Chem. Rev. A, t& 283(1970). b) W.C. Still, J. Org. Chem., 3, c) T. Hiyama, M. Obayashi, I. Mori and H. Nozaki, 3. Org. Chem., 9, 912 3063(1976). (1983).
6.
Acysilanes from silyl anions, a) with Ph3SiLi, see N. Duffaut, J. Dunogues, C. Biran and b) with (Me3Si)2, see A. Ricci, A. R. Calas, J. Organomet. Chem., 161, C23(1978) Degl'Innocenti, S. Chimichi, M. Fiorenza and G. Rossini, J. Org. Chem., 50, 130(1985).
7.
L. Roesch
8.
J.A. Miller
9.
This research (Received
and G. Altnau,
J. Organomet.
and G. Zweifel,
in
was supported Japan
Chem., 1, 96(1968);
Synthesis,
Chem., 195, 47(1980); 288(1981).
by the Korea Research
3 March
1987)
1734(1984).
Foundation.
b) C. Shih and J.S.
Chem. Ber., 112,
Tetra-
3934(1979).
CONVENIENT
PREPARATION
Jahyo Kang*,
OF ACYLTRIMETHYLSILANES
Jae Hyoung
oo40-4039/87 $3.00 + .Oo Pergamon Journals Ltd.
3261-3262,1987
FROM CARBOXYLIC
ACID DERIVATIVES
Lee, Koan Seong Kim, Jae Uk Jeong and Chongsuh
Department
of Chemistry,
Mapoku,
Seoul
Pyun
Sogang University 121, KOREA
Summary : Acylsilanes are prepared in good yields by the reaction of acid chlorides (or anhydrides) with LiAl(SiMe3)4 or LiMeAl(SiMe3)3 in the presence of a catalytic amount of CuCN.
Acylsilanes
are interesting
For some applications carboxylic
class of compounds
of this functionality,
acids was needed
which
undergo
a facile method
of reactions.
for acylsilanes
directly
l-3
from
in literature 4 a number of preparatively useful methods, most of which utilize acyl anion equivalents , due to the difficulty associated with generation of silyl anions under mild conditions. 596 Since trimethylsilyl
in our laboratories
a variety
anion is usually
thought
to be inappropriate
readily
available
especially
Al-Si reagents,
cause of the low ionic character independently A1(SiMe3)3 ponding
especially
in the presence
1).
verted
in LiAl(SiMe3)4
was transferred
that even functionalized
Furthermore,
addition
presumably
silylation
reactions
the available
amounts.
conducted
trimethylsilyl Notably,
The following
(0.036 g, 0.40 mmol) LiA1(SiMe3)4 0.5 h. solution
methyl
tion of aqueous
acylsilane
(4.0 mmol).
to methyl
carbamoyl
The mixture
of methyllithium
rate
ketones
chlorides,
was warmed
The usual work-up
esters,
to the hitherto
nitriles
useless
For those reactions
3261
= 2)
in any significant
is representative.
To CuCN
27.6 mL of 0.145 M solution it was stirred
with stirring
to O'C, and quenched
was added at O'C to a stirred
for the
number of
(RCOC1/Al(SiMe3)3*LiMe
up to O°C, where
followed
with Al(SiMe3)3,
for
addi-
gave 1.63 g
an equimolar
of Al(SiMe3)3
of
to the black
by dropwise
by Si02 chromatography
solution
con-
(Entry 12).
was not observed
was warmed
(Table
That the
that, due to the smaller
(1.35 g, 10.0 mmol) was added dropwise
acid.
useful
were individually
ate complex, which was also effective except
to
trimethylsilyl
(Entries 4 and 10).
can be utilized
for hexanoyltrimethylsilane
After 2 h, the mixture
sulfuric
anhydrides
groups, more LiMeAl(SiMe 3 ) 3 reagent transfer
of the corres-
to be more satisfactory,
amount of methyllithium
fashion
treated
the tricoordinated
quantity
at a synthetically
yields
itself,
acid chlorides
were
the be-
mole ratio of acid chloride
and phthalic
in satisfactory
in a similar
(95 %) of hexanoyltrimethylsilane.8 solution
The optimal
the corresponding
procedure
chloride
at -78'C.
Generally,
proved
in 33 mL THF at -78'C was added dropwise
in ether
Hexanoyl
conditions:
, It was
to be attractive
acid chlorides
of only a minute
7.
In this regard,
seemed
Consequently,
LiAl(SiMe3)4
benzoic
of an equivalent
provided
acid derivatives.
to acid chloride
acylsilanes
basic conditions
that only part of the four available
could also be silylated;
Al(SiMe3)3
formation
of CuCN (10 mole W).
system was inert to ketones,
etc. suggests
was needed.
under various with
the ate complex,
to the corresponding
present
of the Al-Si bond.
was close to 2.5, implying
Anhydrides
under strongly
Al(SiMe 3 ) 3 and LiAl(SiMe3)47,
reactions
whereas
generated
for carboxylic
the above reagents
acylsilane,
LiAl(SiMe3)4 groups
with
gave incomplete
even though there are available
ether
in pentane-THF
3262
(The pentane
was a solvent
CuCN (0.1 molar Stirring
equiv.
for the aluminum
at O°C for 0.5 h furnished Table Starting Material
Entry
reagent.).
After stirring
at O°C for 0.5 h, solid
to the acid chloride
1.
to be added) was added under nitrogen 9 the active silylating agent.
Preparation
Reagentb
blanket.
of hcyltrimethylsilanesa
Mole Ratio'
Reaction Timed
Yielde
Product
1
n-C5HllCOC1
2.5
2h
95 %
n-C5HllCOSiMe3
2
PhCOCl 1,
2.5
1.5
93
PhCOSiMe3
2.0
2
73
3 4
(PhC0)20
2.5
1.5
88
5
PhCH2COC1
2.5
1.5
89
2.5
1.5
90
A
2.5
1.75
89
A
2.5
1.75
89
A
2.5
2.5
86
A
2.5
1.5
81
B
2.0
2
90
B
2.0
2
52
6
II
PhCH2COSiMe3
CH2COSiMe3
CH2COC1 t-BuCOCl
10 11
t-BuCOSiMe
D-
3
COSiMe3
AcOCH2COSiMe3
COCl
5J 0
12
CN/
' Mole ratio of a See text for reaction condition. b A, LiAl(SiMe ) ; B, LiMeAl(SiMe ) acid derivative to the reagent. d At -78OC. e Bazei on the amount o 2 zcid derivative used
.
References Act. Chem. Res., 7, 77(1974).
1.
A.G. Brook, Adv. Organomet.
2.
b) H.J. Reich, a) D. Schinzer and C.H. Heathcock, Tetrahedron Lett., 2, 1881(1981). c) J. Enda and I. M.J. Kelly, R.E. Olson and R.C. Holtan, Tetrahedron, 2, 949(1983). d) H.J. Reich and E.K. Eisenhart, J. Org. Kuwajima, 3. Am. Chem. Sot., 107, 5495(1985). Chem. , 49, 5282(1984).
3.
a) M.E. Scheller and B. Frei, Helv. Chim. Acta, 67, Swenton, J. Org. Chem., 47, 2668(1982).
4.
For most recent one; T. Mandai, 11. Yamaguchi, Y. Nakayama, J. Otera and M. Kawada, hedron Lett., 6, 2675(1985); T. Aoyama and T. Shioiri, ibid, 7, 2005(1986).
5.
a) D.C. Davis, Organomet. Chem. Rev. A, t& 283(1970). b) W.C. Still, J. Org. Chem., 3, c) T. Hiyama, M. Obayashi, I. Mori and H. Nozaki, 3. Org. Chem., 9, 912 3063(1976). (1983).
6.
Acysilanes from silyl anions, a) with Ph3SiLi, see N. Duffaut, J. Dunogues, C. Biran and b) with (Me3Si)2, see A. Ricci, A. R. Calas, J. Organomet. Chem., 161, C23(1978) Degl'Innocenti, S. Chimichi, M. Fiorenza and G. Rossini, J. Org. Chem., 50, 130(1985).
7.
L. Roesch
8.
J.A. Miller
9.
This research (Received
and G. Altnau,
J. Organomet.
and G. Zweifel,
in
was supported Japan
Chem., 1, 96(1968);
Synthesis,
Chem., 195, 47(1980); 288(1981).
by the Korea Research
3 March
1987)
1734(1984).
Foundation.
b) C. Shih and J.S.
Chem. Ber., 112,
Tetra-
3934(1979).