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Catalyzed cycloaddition reactions of α-silyloxy-α,β-unsaturated ketone and aldehyde
Tetrahedron Printed in
Letters,Vol.23,No.l6,pp Great Britain
CATALYZED
CYCLOADDITION
REACTIONS
Tadashi
Nagoya
Summary
with
of
:
The
presence
Applied
of
furnish
the
as
of
are
functionalized
2x-components;
cycloaddition (II)
carbonyl in
of
Nagoya,
Japan)
and
respectively
to
react
prepared
compounds
with
by
(I) 4
acetonitrile.
in
the
Along
this
development
attention
has
line,
of
been
presence
of
of
trimethylsilyl
a typical
without the
As
[4+2]
in
To
the
a catalyst
for
effective;
within yield.
under
The
synthesis
of
other
dienes
adduct
was
the
of
paid
The
the
chloride
yield of
vinyl
this
product -10
45% best
by
also
at our
no
to
-78'C
or
in
and to
was of
smoothly
isoprene
to
starting
was
report
BF465%
unsaturated a-keto
triethylamine
reaction
of
the
reaction
catalyzed
yield
onium
Nevertheless
give
silyl (1)
wish
of
ethers
in
pentane
R2,R3=-(CH2)2-
R3=OEt
the
this
growth
silyl enol
corresponding
and
appreciable
Et30 +
or
knowledge
ketone
from
chosen
reaction.
catalysis
oxidation
obtained
first
SnC14
structure
proceeded
1 R1,R2=H
expected,
Diels-Alder
methyl
1 hr
have be
However,
adduct
2).
we
might
a catalyst.
(entry
it
example,
isoprene:
the
a-silyloxy-a,B-unsaturated
a catalyst.
silylations
reaction
dienol
3-(trimethylsilyl)oxy-3-buten-2-one 3 class of dienes. We
(11)
with
the
Diels-Alder
limited
usual
with
for
compounds.
reactivity
the
the
candidates
little
the
(1)
As
aldehyde
in
5 R1=H
(1) -
ALDEHYDE
Engineering,
464,
ketone
cycloadducts
remarkable
them
compounds
or
[4+3]
the
among
divergent
were
AND
Ohno
Faculty
Chikusa-ku,
good
contrast,
here
silanes
Masatomi
Chemistry,
cyclic
allowed
known
the
and
a-silyloxy-cz,8-unsaturated and
olefins
hitherto
carbonyl
KETONE
a catalyst.
chemistry 2 4x-components. In
ethers
Organic
[4+2]
organosilicon as
Ishibashi,
Furo-cho,
reactions
afforded
Oxygen-substituted to
Yukio
University,
diene
OFa-SILYLOXY-o$UNSATLJRATED
*
Sasaki,
(Institute
0040-4039/82/161693-04$03.00/O 01982 Pergamon Press Ltd.
1693-1696,1982
reacted
at salt
the room is
our at
known took
reagent place
reaction
give
temperature
not
precedented
examination
room
to
as
indicated
temperature
1-methyl-4-acetylcyclohexene
@)in
72%
unequivocally
determined by the independent 5 t-BuOK and 0 The reactions of -1 with -8 with 2' to give the expected products. The [4+2] cyclo-
isoprene
and 1693
3 _*
Interestingly,
enol
silyl
ethers
1694
derived
from cyclic
addition
a-diketones
reactions
(5 and 5) underwent
unfortunately
five-membered
decomposition
of the reagent
4 was unsuccessful under
The chemical
behavior
In this
case
of silyl SnC14
enol
ether
catalyzed
compounds;
of the concomitant
conditions.
comparison 6
[4+2] cyclo-
bicyclic
because
the employed
in -15 was confirmed by the spectral with known cis-9-hydroxy-1-decalone.
contrast:
the similar
to give the bridgehead-hydroxylated
The cis-fusion
of the hydrogenated
of pyruvaldehyde
product
of -15
(2) is in good
the reaction
of -2 with butadiene at -78°C better than the onium salt, but the product was found to be not [4+2] but [4+3] 7 cycloadduct arising from the ally1 cation type of reaction. The assigned seven-membered
ring structure was affirmed by the identity of the hydrogenated 8 of -18 with the authentic sample. Similarly, the reactions of 2 with cyclopentadiene and furan afforded bicyclo[3.2.l]octanes -19 and -20 respectively; the latter formed only one isomer with a hydroxyl group exe-substituted. These
product
results
are summarized
On the other
hand,
pentadiene
afforded
conditions
as above.
originate groups with
in Table
the analogous
neither
from the extent
for
the catalyst While
them.
about
of discrete
fully
OSiMe3
may
the carbonyl
of the catalyst
in their frontier orbitals 9 that with the aldehyde
nature,
opened
ally1
cation,
COMe OSiMe3
which
is COMe OH
H20
SnC14 1
5 ZMe?
,;‘.,
R=H Consequently unsaturated
trated
catalyzed
in reactivity
with
formation
changes
and cyclo-
the same
[4+3] cycloaddition.
;c=o
of cyclic
under
coordinates
R=Me d
butadiene
difference
the complex
of allyl-cation-like
to the formation
responsible
that the observed
to which
contribution
of 1 with
[4+3] cycloadduct
(l_, 3, 2 and 5) brings
the ketones
(2_) leads
reactions
[4+2] nor
We believe
and thus polarizes
due to partial
1.
the present
ketone
Further
cr-ketols.
synthone.
Spiro-furanone
(a),
method
of the obtained
cyclization
to the known
OH COMe
MeOH/H20 Y:a2%
reactions
BH
-10
of -10 with 11 procedure.
of a-silyloxy-o,Bfor the preparation
a-ketol
loof _10 to cyclohexenone
NaI04
-21
a convenient
conversions
2) Anionic according
_
-
cycloaddition
provide
1) NaI04-oxidation
as follows:
as a ketene
catalyzed
and aldehyde
H20
,_&SiMe3 0SnC14
are illusimplying
(a),
ethyl
formate
to
HCOOEt 0
NaH/Et20 -22
Y:15%
1
1695
Table 1. Catalyzed Cycloaddition Reactions of 1 - 5 with Some Dienes.a
entry silane diene 1
b conditions 1. 2. 3.
IRd cm-l
NMRe 6
R‘oc[H,cH 1650' 3500’ 750 1710 2.20 5.66 (3H' (2H1 m s' , CH=CH) CH3CO): 3.30 (lH, s, OH),
-1 R=H
2
productC vield
-1
R=Me
S [M
-78 rt
2 R=H Y:!9% [Y:35%] 7 10 R=Me 3500, 1715 5.25 (lH, m, CH=C), 3.28 (lH, s, OH), 121 - Y:45% 1645, 760 2.20 (3H, s, CH3CO), 1.70 (3H, br s, [Y:65%] CH3C=C). Mass spectrum (30 eV), m/e 154 (M+), 136 (M+-H20).
-x 3
-1
M
rt
12
b, I
4
-1
Ph.,+.q M
rt
12
Q I
5
-1
0
6
0
M
3500, 1710 5.30 and 5.04 (each lH, m, CH=C), 3.23 (lH, s, OH), 2.18 (3H, s, CH3CO), 1.67 kl, 1670 and 1.60 (each 3H, br s, CH3C=C). -11 Y:72%
OH 3500, 1705 7.13 (5H, br oh fi0CH31655, 1600 (each lH, br 3.72 (lH, s, -12 Y:74% 1.37 (3H, s,
f+
OH COCH3 -13 Y:40%
6
2
&
M
rt
s, phenyl), 5.98 and 5.60 ABq, .J=12Hz, CH=CH), OH), 3.28 (lH, br s, CHPh), CH3CO).
3550, 1720 6.12 and 5.86 (each lH, dd, .T=3and 5 Hz CH=CH), 3.38 (lH, S, OH), 1.16 (3H, S, CH3CO).
3500, 1670 7.1-8.2 (5H, m, phenyl), 5.23 (lH, br s, CH=C), 3.52 (lH, s, OH), 1.67 (3H, br s, COPh 1605 CH3C=C). -14 Y:ao%
12 noi
II OH -5
3500, 1700 5.63 (2H, m, CH=CH), 3.86 (lH, s, OH). ct3- 'A 15 R=H Y:48% 12 16 R=Me 3500, 1705 5.35 (lH, m, CH=C), 4.07 (lH, s, OH), Y:70% 1.75 (3H, br s, CH3C=C).
L
M
ITiT
l2
-5
R=H R=Me
M
rt
9
-6
-
M
rt
12
10
-2
w
S
-78
213
11
-2
S
-78
5
OH ?zb
I
3550, 1685
5.58 (2H, m, CH=CH), 3.78 (lH,
S,
014).
17 Y:72% 3500, 1710 5.85 (2H, m, CH=CH), 4.33 (lH, dd, J=5 and 11 Hz, CEOH), 3.83 (lH, s, OH). Mass spectrum (75 eV), m/e 126 (M+), 108 (ti-H20) -18 Y:32% 3500, 1710 5.98 (2H, m, CH=CH), 4.05 (lH, d, .l=4Hz, CEOH), 3.29 (lH, s, OH). 4
3450, 1700
6 Hz,and 6.15 CH=CH), 5.92 3.77 (each(lH, lH, dd, s, OH), J=3 and 3.57 (lH, br s, CEOH).
-l9 Y:72% (endo:exo=73:27)
1696
Table 1. continued 12 2 q
S
-78
l/6
8
3400, 1700 6.30 and 6.22 (each lH, AB q, 5=5.5 Hz, CH=CH), 5.10 and 5.02 (each lH, br s, 4 Cl-H and C2-H), 4.37 (lH, br d, J=5 Hz, 0 C5-H), 3.60 (lH, s, OH), 2.92 (lH, dd, .I=5and 15 Hz, C4-H), 2.42 (lH, dd, -20 Y:43% J=l and 15 Hz, C4-H).
a Elemental analyses were found to be satisfactory.
b
Reaction conditions: 1. catalyst:S, SnC14;
M, Et30+ BF4-. 2. temperature in 'C: rt, room temperature. 3. reaction time in hour. ' In entry 2, 3, 4, 6 and 8, there are depicted the structures of the major product of the possible regioisomers. The NMR spectra of the product mixtures suggested more than 86% "para" selectivity (integrationratio of acetyl or olefinic signals. Eu(fod)3 was employed if required). 3b mp: 2, 79-80°C (lit. mp 80-82'C). 2, 58-60°C. endo-19, 78-82'C. exo-19, 119-121'C. 2, d 76-78OC. All others were obtained in oil. Crystalline 13, 11, 19 and 20 were scanned in KBr disks and all others in neat. e Solvents used are CDC13 for 16 and 20, and CC14 for all others.
In NMR spectra of 2,
19 and 20, coupling constants between Cl-H and C2-H support
endo- and exo-positions of the hydroxyl groups; H. M. R. Hoffmann, K. E. Clemens, and R. H. Smithers, J. Am. Chem. Sot., 94, 3940 (1972).
Typical Procedure.
To a solution of unsaturated silane (1 mmol) and diene (1.5 mmol) in dry
CH2C12 (3 ml) was added 1 eq. of catalyst in dry CH2C12 (1 ml) at the temperature designated in Table 1, and the reaction mixture was stirred for an appropriate time.
After evaporation of
the solvent the residue was treated with MeOH (10 ml) and 1N HCl (1 ml) for 30 min, and poured into ice-water containing NaHC03.
After extraction with ether and evaporation of the solvent,
purification on a silica gel column (CHC13) gave a product. REFERENCES AND NOTES (1) Part 40 of "Molecular Design by Cycloaddition Reaction": Part 39: T. Sasaki, T. Manabe, and K. Hayakawa, Tetrahedron Lett. 22, 2579 (1981). (2) For example, (a) S. Danishefsky, T. Kitahara, C. F. Yan, and J. Morris, J. Am. Chem. SOC., 101,
6996 (1979). (b) P. Brownbridge and T. H. Chan, Tetrahedron Lett., 21_, 3423 (1980).
(3) (a) S. Murai, I. Ryu, Y. Kadono, and N. Sonoda, Chem. Lett., 1219 (1977). (b) R. J. Ardecky, F. A. J. Kerdesky, and M. P. Cava, J. Org. Chem., 46, 1483 (1981). (4) Trimethylsilylationswere performed by the method reported in ref. 2b or 3a. (5) J. N. Gardner, F. E. Carlon, and 0. Gnoj, J. Org. Chem., 22, 3294 (1968). (6) H. 0. House and H. W. Thompson, J. Org. Chem., 28, 164 (1963). (7) (a) H. Sakurai, A. Shirahata, and A. Hosomi, Angew. Chem., 91, 178 (1979). (b) N. Shimizu and T. Tsuno, Chem. Lett., 103 (1979). (8) G. M. Rubottom, M. A. Vazquez, and D. R. Pelegrina, Tetrahedron Lett., 4319 (1974). (9) I. Fleming,"FrontierOrbitals and Organic Chemical Reactions", John-Wiley & Sons, London, 1976; p. 161. (10) C. H. Heathcock, S. D. Young, J. P. Hagen, M. C. Pirring, C. T. White, and D. VanDerveer, J. Org. &em., 45, 3846 (1980). (11) P. Margaretha, Tetrahedron Lett., 4891 (1971). (Received
in Japan
16 January
1982)
Letters,Vol.23,No.l6,pp Great Britain
CATALYZED
CYCLOADDITION
REACTIONS
Tadashi
Nagoya
Summary
with
of
:
The
presence
Applied
of
furnish
the
as
of
are
functionalized
2x-components;
cycloaddition (II)
carbonyl in
of
Nagoya,
Japan)
and
respectively
to
react
prepared
compounds
with
by
(I) 4
acetonitrile.
in
the
Along
this
development
attention
has
line,
of
been
presence
of
of
trimethylsilyl
a typical
without the
As
[4+2]
in
To
the
a catalyst
for
effective;
within yield.
under
The
synthesis
of
other
dienes
adduct
was
the
of
paid
The
the
chloride
yield of
vinyl
this
product -10
45% best
by
also
at our
no
to
-78'C
or
in
and to
was of
smoothly
isoprene
to
starting
was
report
BF465%
unsaturated a-keto
triethylamine
reaction
of
the
reaction
catalyzed
yield
onium
Nevertheless
give
silyl (1)
wish
of
ethers
in
pentane
R2,R3=-(CH2)2-
R3=OEt
the
this
growth
silyl enol
corresponding
and
appreciable
Et30 +
or
knowledge
ketone
from
chosen
reaction.
catalysis
oxidation
obtained
first
SnC14
structure
proceeded
1 R1,R2=H
expected,
Diels-Alder
methyl
1 hr
have be
However,
adduct
2).
we
might
a catalyst.
(entry
it
example,
isoprene:
the
a-silyloxy-a,B-unsaturated
a catalyst.
silylations
reaction
dienol
3-(trimethylsilyl)oxy-3-buten-2-one 3 class of dienes. We
(11)
with
the
Diels-Alder
limited
usual
with
for
compounds.
reactivity
the
the
candidates
little
the
(1)
As
aldehyde
in
5 R1=H
(1) -
ALDEHYDE
Engineering,
464,
ketone
cycloadducts
remarkable
them
compounds
or
[4+3]
the
among
divergent
were
AND
Ohno
Faculty
Chikusa-ku,
good
contrast,
here
silanes
Masatomi
Chemistry,
cyclic
allowed
known
the
and
a-silyloxy-cz,8-unsaturated and
olefins
hitherto
carbonyl
KETONE
a catalyst.
chemistry 2 4x-components. In
ethers
Organic
[4+2]
organosilicon as
Ishibashi,
Furo-cho,
reactions
afforded
Oxygen-substituted to
Yukio
University,
diene
OFa-SILYLOXY-o$UNSATLJRATED
*
Sasaki,
(Institute
0040-4039/82/161693-04$03.00/O 01982 Pergamon Press Ltd.
1693-1696,1982
reacted
at salt
the room is
our at
known took
reagent place
reaction
give
temperature
not
precedented
examination
room
to
as
indicated
temperature
1-methyl-4-acetylcyclohexene
@)in
72%
unequivocally
determined by the independent 5 t-BuOK and 0 The reactions of -1 with -8 with 2' to give the expected products. The [4+2] cyclo-
isoprene
and 1693
3 _*
Interestingly,
enol
silyl
ethers
1694
derived
from cyclic
addition
a-diketones
reactions
(5 and 5) underwent
unfortunately
five-membered
decomposition
of the reagent
4 was unsuccessful under
The chemical
behavior
In this
case
of silyl SnC14
enol
ether
catalyzed
compounds;
of the concomitant
conditions.
comparison 6
[4+2] cyclo-
bicyclic
because
the employed
in -15 was confirmed by the spectral with known cis-9-hydroxy-1-decalone.
contrast:
the similar
to give the bridgehead-hydroxylated
The cis-fusion
of the hydrogenated
of pyruvaldehyde
product
of -15
(2) is in good
the reaction
of -2 with butadiene at -78°C better than the onium salt, but the product was found to be not [4+2] but [4+3] 7 cycloadduct arising from the ally1 cation type of reaction. The assigned seven-membered
ring structure was affirmed by the identity of the hydrogenated 8 of -18 with the authentic sample. Similarly, the reactions of 2 with cyclopentadiene and furan afforded bicyclo[3.2.l]octanes -19 and -20 respectively; the latter formed only one isomer with a hydroxyl group exe-substituted. These
product
results
are summarized
On the other
hand,
pentadiene
afforded
conditions
as above.
originate groups with
in Table
the analogous
neither
from the extent
for
the catalyst While
them.
about
of discrete
fully
OSiMe3
may
the carbonyl
of the catalyst
in their frontier orbitals 9 that with the aldehyde
nature,
opened
ally1
cation,
COMe OSiMe3
which
is COMe OH
H20
SnC14 1
5 ZMe?
,;‘.,
R=H Consequently unsaturated
trated
catalyzed
in reactivity
with
formation
changes
and cyclo-
the same
[4+3] cycloaddition.
;c=o
of cyclic
under
coordinates
R=Me d
butadiene
difference
the complex
of allyl-cation-like
to the formation
responsible
that the observed
to which
contribution
of 1 with
[4+3] cycloadduct
(l_, 3, 2 and 5) brings
the ketones
(2_) leads
reactions
[4+2] nor
We believe
and thus polarizes
due to partial
1.
the present
ketone
Further
cr-ketols.
synthone.
Spiro-furanone
(a),
method
of the obtained
cyclization
to the known
OH COMe
MeOH/H20 Y:a2%
reactions
BH
-10
of -10 with 11 procedure.
of a-silyloxy-o,Bfor the preparation
a-ketol
loof _10 to cyclohexenone
NaI04
-21
a convenient
conversions
2) Anionic according
_
-
cycloaddition
provide
1) NaI04-oxidation
as follows:
as a ketene
catalyzed
and aldehyde
H20
,_&SiMe3 0SnC14
are illusimplying
(a),
ethyl
formate
to
HCOOEt 0
NaH/Et20 -22
Y:15%
1
1695
Table 1. Catalyzed Cycloaddition Reactions of 1 - 5 with Some Dienes.a
entry silane diene 1
b conditions 1. 2. 3.
IRd cm-l
NMRe 6
R‘oc[H,cH 1650' 3500’ 750 1710 2.20 5.66 (3H' (2H1 m s' , CH=CH) CH3CO): 3.30 (lH, s, OH),
-1 R=H
2
productC vield
-1
R=Me
S [M
-78 rt
2 R=H Y:!9% [Y:35%] 7 10 R=Me 3500, 1715 5.25 (lH, m, CH=C), 3.28 (lH, s, OH), 121 - Y:45% 1645, 760 2.20 (3H, s, CH3CO), 1.70 (3H, br s, [Y:65%] CH3C=C). Mass spectrum (30 eV), m/e 154 (M+), 136 (M+-H20).
-x 3
-1
M
rt
12
b, I
4
-1
Ph.,+.q M
rt
12
Q I
5
-1
0
6
0
M
3500, 1710 5.30 and 5.04 (each lH, m, CH=C), 3.23 (lH, s, OH), 2.18 (3H, s, CH3CO), 1.67 kl, 1670 and 1.60 (each 3H, br s, CH3C=C). -11 Y:72%
OH 3500, 1705 7.13 (5H, br oh fi0CH31655, 1600 (each lH, br 3.72 (lH, s, -12 Y:74% 1.37 (3H, s,
f+
OH COCH3 -13 Y:40%
6
2
&
M
rt
s, phenyl), 5.98 and 5.60 ABq, .J=12Hz, CH=CH), OH), 3.28 (lH, br s, CHPh), CH3CO).
3550, 1720 6.12 and 5.86 (each lH, dd, .T=3and 5 Hz CH=CH), 3.38 (lH, S, OH), 1.16 (3H, S, CH3CO).
3500, 1670 7.1-8.2 (5H, m, phenyl), 5.23 (lH, br s, CH=C), 3.52 (lH, s, OH), 1.67 (3H, br s, COPh 1605 CH3C=C). -14 Y:ao%
12 noi
II OH -5
3500, 1700 5.63 (2H, m, CH=CH), 3.86 (lH, s, OH). ct3- 'A 15 R=H Y:48% 12 16 R=Me 3500, 1705 5.35 (lH, m, CH=C), 4.07 (lH, s, OH), Y:70% 1.75 (3H, br s, CH3C=C).
L
M
ITiT
l2
-5
R=H R=Me
M
rt
9
-6
-
M
rt
12
10
-2
w
S
-78
213
11
-2
S
-78
5
OH ?zb
I
3550, 1685
5.58 (2H, m, CH=CH), 3.78 (lH,
S,
014).
17 Y:72% 3500, 1710 5.85 (2H, m, CH=CH), 4.33 (lH, dd, J=5 and 11 Hz, CEOH), 3.83 (lH, s, OH). Mass spectrum (75 eV), m/e 126 (M+), 108 (ti-H20) -18 Y:32% 3500, 1710 5.98 (2H, m, CH=CH), 4.05 (lH, d, .l=4Hz, CEOH), 3.29 (lH, s, OH). 4
3450, 1700
6 Hz,and 6.15 CH=CH), 5.92 3.77 (each(lH, lH, dd, s, OH), J=3 and 3.57 (lH, br s, CEOH).
-l9 Y:72% (endo:exo=73:27)
1696
Table 1. continued 12 2 q
S
-78
l/6
8
3400, 1700 6.30 and 6.22 (each lH, AB q, 5=5.5 Hz, CH=CH), 5.10 and 5.02 (each lH, br s, 4 Cl-H and C2-H), 4.37 (lH, br d, J=5 Hz, 0 C5-H), 3.60 (lH, s, OH), 2.92 (lH, dd, .I=5and 15 Hz, C4-H), 2.42 (lH, dd, -20 Y:43% J=l and 15 Hz, C4-H).
a Elemental analyses were found to be satisfactory.
b
Reaction conditions: 1. catalyst:S, SnC14;
M, Et30+ BF4-. 2. temperature in 'C: rt, room temperature. 3. reaction time in hour. ' In entry 2, 3, 4, 6 and 8, there are depicted the structures of the major product of the possible regioisomers. The NMR spectra of the product mixtures suggested more than 86% "para" selectivity (integrationratio of acetyl or olefinic signals. Eu(fod)3 was employed if required). 3b mp: 2, 79-80°C (lit. mp 80-82'C). 2, 58-60°C. endo-19, 78-82'C. exo-19, 119-121'C. 2, d 76-78OC. All others were obtained in oil. Crystalline 13, 11, 19 and 20 were scanned in KBr disks and all others in neat. e Solvents used are CDC13 for 16 and 20, and CC14 for all others.
In NMR spectra of 2,
19 and 20, coupling constants between Cl-H and C2-H support
endo- and exo-positions of the hydroxyl groups; H. M. R. Hoffmann, K. E. Clemens, and R. H. Smithers, J. Am. Chem. Sot., 94, 3940 (1972).
Typical Procedure.
To a solution of unsaturated silane (1 mmol) and diene (1.5 mmol) in dry
CH2C12 (3 ml) was added 1 eq. of catalyst in dry CH2C12 (1 ml) at the temperature designated in Table 1, and the reaction mixture was stirred for an appropriate time.
After evaporation of
the solvent the residue was treated with MeOH (10 ml) and 1N HCl (1 ml) for 30 min, and poured into ice-water containing NaHC03.
After extraction with ether and evaporation of the solvent,
purification on a silica gel column (CHC13) gave a product. REFERENCES AND NOTES (1) Part 40 of "Molecular Design by Cycloaddition Reaction": Part 39: T. Sasaki, T. Manabe, and K. Hayakawa, Tetrahedron Lett. 22, 2579 (1981). (2) For example, (a) S. Danishefsky, T. Kitahara, C. F. Yan, and J. Morris, J. Am. Chem. SOC., 101,
6996 (1979). (b) P. Brownbridge and T. H. Chan, Tetrahedron Lett., 21_, 3423 (1980).
(3) (a) S. Murai, I. Ryu, Y. Kadono, and N. Sonoda, Chem. Lett., 1219 (1977). (b) R. J. Ardecky, F. A. J. Kerdesky, and M. P. Cava, J. Org. Chem., 46, 1483 (1981). (4) Trimethylsilylationswere performed by the method reported in ref. 2b or 3a. (5) J. N. Gardner, F. E. Carlon, and 0. Gnoj, J. Org. Chem., 22, 3294 (1968). (6) H. 0. House and H. W. Thompson, J. Org. Chem., 28, 164 (1963). (7) (a) H. Sakurai, A. Shirahata, and A. Hosomi, Angew. Chem., 91, 178 (1979). (b) N. Shimizu and T. Tsuno, Chem. Lett., 103 (1979). (8) G. M. Rubottom, M. A. Vazquez, and D. R. Pelegrina, Tetrahedron Lett., 4319 (1974). (9) I. Fleming,"FrontierOrbitals and Organic Chemical Reactions", John-Wiley & Sons, London, 1976; p. 161. (10) C. H. Heathcock, S. D. Young, J. P. Hagen, M. C. Pirring, C. T. White, and D. VanDerveer, J. Org. &em., 45, 3846 (1980). (11) P. Margaretha, Tetrahedron Lett., 4891 (1971). (Received
in Japan
16 January
1982)