Rhodium-catalyzed acylation of vinylsilanes with acid anhydrides

Article abstract of DOI:10.1246/bcsj.78.477

A catalytic acylation of vinylsilane with acid anhydride is accomplished by the use of [RhCl(CO)₂]₂, in which the transmetalation between vinylsilane and rhodium(I) carbonyl complex plays a key role. The application of this acylation reaction to (1-acyloxyvinyl)silanes provides synthetic methods for α-acyloxy enones, α-diketones, and their derivatives.

Full text of DOI:10.1246/bcsj.78.477

Ó 2005 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 78, 477–486 (2005)
477
Rhodium-Catalyzed Acylation of Vinylsilanes with Acid Anhydrides
ꢀ
Motoki Yamane, Kazuyoshi Uera, and Koichi Narasaka
Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033
Received October 12, 2004; E-mail: narasaka@chem.s.u-tokyo.ac.jp
A catalytic acylation of vinylsilane with acid anhydride is accomplished by the use of [RhCl(CO)2]2, in which the
transmetalation between vinylsilane and rhodium(I) carbonyl complex plays a key role. The application of this acylation
reaction to (1-acyloxyvinyl)silanes provides synthetic methods for ꢀ-acyloxy enones, ꢀ-diketones, and their derivatives.
The acylation of vinylsilanes proceeds in a regioselective
manner to afford ꢀ,ꢁ-unsaturated ketones and is generally per-
formed by treatment with acid halides or acid anhydrides in the
presence of Lewis acids.1 Because more than a stoichiometric
amount of strong Lewis acids such as AlCl3 is indispensable in
this type of acylation, the development of a catalytic process
has been desired from a synthetic point of view.2 Recently,
we developed a catalytic acyclation of vinylsilanes with acid
anhydrides by the use of a rhodium complex.3 This paper gives
a full account of the catalytic acylation reaction.
enol form of acylsilanes.
Me
Me
O
O
Me
OMe
Me
1) LDA
2) MeI
+
SiMe2Ph
Ph
SiMe2Ph
Ph
SiMe2Ph
Ph
3
4
2 : 3 82%
ð1Þ
5 mol%
O
H
OMe H
[RhCl(CO)2]2
CH3COOH
Me
Me
Me
Ph
Ph
Results and Discussion
+
3 + 4
Toluene
100 °C, 12 h
Rhodium-Catalyzed Acylation of Vinylsilanes with Acid
Anhydrides. We studied the transition metal-catalyzed intra-
molecular acylation of acetylenic acylsilanes where the key
step is the transmetalation between a rhodium(I) carbonyl
complex, [RhCl(CO)2]2, and acetylenic acylsilane 1. The reac-
tion proceeds via generation of acylrhodium intermediates,
which in turn add to the intramolecular acetylenic moiety to
give alkylidenecyclopentanones 2 (Scheme 1).4
We wondered whether the transmetalation proceeds in the
keto form (acylsilane) or the enol form ((1-hydroxyvinyl)-
silane), because ꢀ-proton of acylsilane is acidic, as the pKa
of acetyltrimethylsilane is reported to be 16.4.5 ꢀ,ꢀ-Dimethyl-
acylsilane 3 and (1-methoxyvinyl)silane 4, which correspond
to the fixed keto and enol forms of acylsilane 1, respectively,
were prepared and the mixture was submitted to the intramo-
lecular acylation reaction (Eq. 1 and 2). As both of the expect-
ed cyclization products 5 and 6 were obtained from these two
substrates, the transmetalation may occur from either keto or
(2 : 3)
5
73%
6
33%
based on 3
based on 4
ð2Þ
Since it was found that [RhCl(CO)2]2 had the ability to ac-
tivate not only the sp2 C–Si bond of acylsilane 3 but also that
of (1-alkoxyvinyl)silane 4, we tried to incorporate this trans-
metalation process to develop a catalytic acylation of vinyl-
silanes with acid anhydrides.
Firstly, 1-alkenylsilane 7a was treated with 3 molar amounts
of acetic anhydride and 5 mol% of [RhCl(CO)ꢁ2]2 in toluene,
vinylsilane 7a was consumed gradually at 80 C and it was
found the acylation product, ꢀ,ꢁ-unsaturated ketone 8a, was
obtained in 55% yield (Eq. 3).
5 mol%
Ph(CH2)2
7a [RhCl(CO)2]2
Me
Ph(CH2)2
8a 55%
SiMe2Ph
+
Toluene
80 °C, 40 h
O
(MeCO)2O
ð3Þ
O
5 mol% [RhCl(CO)2]2
CH3COOH
O
H
To obtain insight into the initial step of this catalytic acyla-
tion, vinylsilane 7a and acetic anhydride were allowed to react
independently with a stoichiometric amount of [RhCl(CO)2]2
and each of these reactions was monitored by 1H NMR. When
vinylsilane 7a was treated with a stoichiometric amount of
[RhCl(CO)2]2 in toluene at 80 ꢁC, chloro(dimethyl)phenyl-
silane, dimethyl(phenyl)silanol, and 1,1,3,3-tetramethyl-1,3-
diphenyldisiloxane were detected in 38%, 9%, and 33% yields,
respectively (Eq. 4). To the contrary, no reaction was observed
in the reaction of aceticꢁanhydride and a stoichiometric amount
of [RhCl(CO)2]2 at 80 C for 5 h (Eq. 5).
SiMe2Ph
Ph
Ph
Toluene, 70 °C, 12 h
1
2
82%
- XSiMe2Ph (X = Cl, OCOCH3)
O
RhI(CO)n
Ph
O
RhI(CO)n
Ph
Scheme 1. Rhodium-catalyzed acylation of alkyne with
acylsilane 1.
Published on the web March 11, 2005; DOI 10.1246/bcsj.78.477

478 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Rhodium-Catalyzed Acylation of Vinylsilanes
Table 1. Rhodium(I)-Catalyzed Acylation of Dimethyl-
(phenyl)vinylsilanes 7aaÞ
Ph(CH2)2
+
1/2 [RhCl(CO)2]2
SiMe2Ph
Toluene-d8
80 °C, 10 h
7a
5 mol%
[RhCl(CO)2]2
Ph(CH2)2
R
SiMe2Ph
Ph(CH2)2
Ph(CH2)2
+
+
ClSiMe2Ph HOSiMe2Ph (Me2PhSi)2O
7a
RhI(CO)n
+
O
8
A
38%
9%
33%
(RCO)2O
ð4Þ
(RCO)2O
R
Entry
Solvent
Temp/ꢁC Time/h Yield/%
+
(MeCO)2O
1/2 [RhCl(CO)2]2
No Reaction
Toluene-d 8
80 °C, 5 h
1
2
3
4
5
6
7
Toluene
Toluene
Me
Me
Me
Et
i-Pr
t-Bu
Ph
80
100
90
90
90
40
18
7
18
18
6
8a 55
8a 87
8a 84
8b 67
8c 72
8d 78
8e 74bÞ
ð5Þ
1,4-Dioxane
1,4-Dioxane
1,4-Dioxane
1,4-Dioxane
1,4-Dioxane
These facts indicate that vinylrhodium intermediate A is
generated by the transmetalation between [RhCl(CO)2]2 and
vinylsilane 7a at the initial stage. As depicted in Scheme 2,
the oxidative addition of acetic anhydride to the vinylrhodium
A and the reductive elimination occur successively to give
ꢀ,ꢁ-unsaturated ketone 8a.6
90
90
18
a) Molar ratio [RhCl(CO)2]2:vinylsilane 7a:(RCO)2O = 0.05:
1:3. b) Decarbonylation product 9 was obtained in 5% yield.
For the transmetalation between transition metal complexes
and vinylsilanes, the use of fluoride ion or the introduction of
alkoxy or hydroxy groups on the silyl group is essential to ac-
tivate vinylsilanes, as reported in the transition metal-catalyzed
arylation of vinylsilanes.7–9 It is quite noteworthy that the pres-
ent metal exchange between [RhCl(CO)2]2 and non-activated
vinylsilane 7a proceeds without any promoter, although the
details of the transmetalation step are not yet clarified.
This rhodium-catalyzed acylation reaction was screened un-
der various reaction conditions concerning solvents, tempera-
ture, and acid anhydrides (Table 1).
At a higher reaction temperature in 1,4-dioxane, the acyla-
tion proceeded faster and ꢀ,ꢁ-unsaturated ketone 8a was ob-
tained in 84% yield (Entries 2 and 3). Primary, secondary,
and tertiary acid anhydrides could be employed for the acyla-
tion (Entries 4, 5, and 6). In the reaction with benzoic anhy-
dride, the desired phenyl vinyl ketone 8e was obtained in
74% yield with 5% yield of decarbonylation product 9 (Entry
7).10
Ph(CH2)2
Ph
9
Table 2. Rhodium(I)-Catalyzed Acylation of Various Vinyl-
silanes 7aÞ
5 mol%
[RhCl(CO)2]2
Ph(CH2)2
Si
Me
Ph(CH2)2
7
+
1,4-Dioxane, 90 °C
O
(RCO)2O
8a
ꢀ
ꢁ
Recovery of
vinylsilane
Entry
Si
Time/h Yield/%
1
2
3
4
SiMe3
SiMe2Ph (7a)
SiMePh2 (7c)
(7b)
18
7
30
40
82
84
71
21
(8)
(64)
SiPh3
(7d)
a) Molar ratio [RhCl(CO)2]2:vinylsilane 7:(RCO)2O
0.05:1:3.
=
Simple vinylsilanes which have methyl- and phenyl-substi-
tuted silyl groups (Me3Si, Me2PhSi, MePh2Si) can be em-
ployed in the rhodium-catalyzed acylation. The bulkiness of
the silyl group, however, influenced the reaction rate, as shown
in Table 2, and triphenyl(vinyl)silane 7d was acylated quite
slowly (Entry 4).
vinyl)silane 7a, (2-arylvinyl)silane 7f and cyclic vinylsilane
7g reacted smoothly to afford 8f and 8g (Entries 2 and 3). In
the reaction of unsubstituted vinylsilane 7h and 1,3-butadi-
enylsilane 7i, the yields decreased due to polymerization
caused by the nucleophilic attack of vinylrhodium intermedi-
ates to the produced ꢀ,ꢁ-unsaturated ketones,9b,c,11 as exempli-
fied by the formation of 1-phenylpent-4-en-1-one 10 (Entries 4
and 5). The acylation of cis-vinylsilane proceeded slowly com-
pared to its trans-isomer, shown in Entries 6 and 7. In the case
of (2-arylvinyl)silane 7f-cis, benzylideneacetone 8f was ob-
tained in 53% yield, whereas the acylation of (2-alkylvinyl)-
silane 7a-cis afforded ꢀ,ꢁ-enone 8a and other acylation
products: 11-trans, 11-cis, and 12 in 60% total yield (Entries
6 and 7).
Synthesis of ꢀ-Diketones from (1-Acyloxyvinyl)silanes.
ꢀ-Diketones are versatile synthetic intermediates, particularly
in the synthesis of various heterocyclic compounds.12 Al-
though many methods have been developed for the synthesis
of ꢀ-diketones through (i) oxidation,13 (ii) use of masked acyl
anion synthons,14 and (iii) other approaches,15 it is not always
easy to prepare unsymmetrical ꢀ-diketones in a simple man-
ner. We expected this rhodium-catalyzed acylation might pro-
Acylations of several dimethyl(phenyl)vinylsilanes 7a, f–i
were examined, as described in Table 3. As well as (2-alkyl-
RhIX(CO)n
R
Me
R
SiMe2Ph
(X=Cl, OCOMe)
O
R = Ph(CH2)2-
8a
X−SiMe2Ph
7a
III
R
R
RhX(CO)n
RhI(CO)n
A
O
Me
(MeCO)2O
Scheme 2. Proposed mechanism of the rhodium(I)-catalyzed
acylation of vinylsilane 7a.

M. Yamane et al.
Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
479
Table 3. Synthesis of ꢀ,ꢁ-Unsaturated Ketones 8 by Rhodium(I)-Catalyzed Acylation of
Vinylsilanes 7aÞ
(RCO)2O
R
Entry
Vinylsilane
Time/h
Product (Yield/%)bÞ
Ph(CH2)2
Me
Ph(CH2)2
Ph
SiMe2Ph
8a (84)
8f (78)
1
2
Me
Me
7
O
7a
Ph
Me
SiMe2Ph
24
O
7f
O
SiMe2Ph
3
4
5
6
7
Ph
Ph
24
18
30
24
24
8g (68)
8h (39)c)
8i (43)
7g
Ph
Ph
SiMe2Ph
7h
O
Ph
SiMe2Ph
Ph
7i
O
Ph
Me
8f (53)d)
Ph
SiMe2Ph
Me
Me
7f-cis
O
Me
Ph(CH2)2
Ph(CH2)2
8a (18)e)
SiMe2Ph
7a-cis
O
a) Molar ratio [RhCl(CO)2]2:vinylsilane 7:(RCO)2O = 0.05:1:3. The reaction was conduct-
ed in 1,4-dioxane at 90 ꢁC. b) Isolated yield. c) 10 was obtained in 2% yield. d) 7f-cis was
recovered in 15% yield. e) 11-trans, 11-cis, and 12 were obtained in 26%, 5%, and 11%
yields.
Ph Ph
Me
Me Ph
Me
Ph
10
11-trans
11-cis
12
O
O
O
O
ꢁ
anhydride and 5 mol% of [RhCl(CO)2]2 in toluene at 80 C,
the reaction proceeded more rapidly as compared to (non-acet-
oxyvinyl)silane 7b, to afford ꢀ-acetoxy enone 17a in 94%
yield (Table 5, Entry 1).19 In the reaction of ((Z)-1-acetoxy-
vinyl)silane 15, a mixture of ꢀ-acetoxy enones 17a and the
stereoisomer 18 was obtained in 76% total yield (Entry 2).
(1-Benzoyloxyvinyl)silanes 14b and 16 reacted smoothly as
well as the ꢀ-acetoxy derivatives, giving ꢀ-benzoyloxy enones
17b and 19 in excellent yields (Entries 3 and 4).20
Table 4. Synthesis of (1-Acyloxyvinyl)silanes 14–16 from
Acylsilane 13
O
1) LDA, HMPA
O
OCR'
SiMe3
OCR'
THF, −78 °C
R
R
R
+
SiMe3
SiMe3
14, 16
2) (R'CO)2O
−78 °C to rt
O
13a (R = Ph(CH2)2)
13b (R = Ph)
15
Entry
R
R0
Products/%
The acylation of (1-benzoyloxyvinyl)silane 14b with vari-
ous acid anhydrides was screened as summarized in Table 6.
Both primary and secondary carboxylic acid anhydrides gave
acylation products 17b–d in excellent yields (Entries 1–4),
whereas the acylation with pivalic anhydride gave only 7%
yield of 17e (Entry 5). In the reaction with benzoic anhydride,
benzoylation product 17f was obtained in 66% yield with 24%
yield of phenylated product 20 (Entry 6). Trifluoroacetylation
also proceeded and the corresponding diketone 21 was ob-
tained as the hydrate form in 79% yield after the purification
by silica gel column chromatography (Entry 7).
1aÞ
2
3
4
Ph(CH2)2
Me
Me
Ph
14a 61 15
14a 86
14b 86
22
—
—
—
Ph(CH2)2
Ph(CH2)2
Ph
Ph
16
87
a) The reaction was carried out without HMPA.
vide a practical synthetic method for unsymmetrical ꢀ-dike-
tones from (1-acyloxyvinyl)silane, because obtained ꢀ-acyl-
oxy enones could be converted to ꢀ-diketones by hydrolysis
of the vinyl ester part.16
(1-Acyloxyvinyl)silanes 14–16 were prepared by O-acyla-
tion of lithium enolate of the corresponding acylsilanes 13
(Table 4).17 O-Acetylation with acylsilane 13a gave a mixture
of stereoisomers of (1-acyloxyvinyl)silanes 14a and 15 (Entry
1). By the addition of HMPA (Entries 2, 3, and 4), the stereo-
selectivity is improved to give ((E)-1-acyloxyvinyl)silanes
14a, 14b, and 16 excusively.18
Thus obtained ꢀ-benzoyloxy ketones were supposed to be
hydrolyzed under acidic conditions to give ꢀ-diketones,
whereas no reaction occurred when ꢀ-benzoyloxy ketone
17b was refluxed for 30 min in 3 M HCl (1 M = 1 mol dmꢂ3
)
according to the reported procedure for the conversion of enol
esters to ketones.16 It was found that ꢀ-benzoyloxy ketones
17b and 19 could be converted in good yield to ꢀ,ꢀ-dialkoxy
ketones 22a, b and 23 by treatment with K2CO3 in methanol
When (1-acetoxyvinyl)silane 14a was treated with acetic

480 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Rhodium-Catalyzed Acylation of Vinylsilanes
Table 5. Rhodium(I)-Catalyzed Acetylation of (1-Acyloxyvinyl)silanes 14–16 with
Acetic AnhydrideaÞ
Entry
Vinylsilane
Time/h
Product (Yield/%)bÞ
O
O
OCMe
OCMe
1
1.5
Ph(CH2)2
Ph(CH2)2
Me
SiMe3
14a
15
O
17a (94)
SiMe3
OCMe
Me
O
Ph(CH2)2
2cÞ
5
3
Ph(CH2)2
17a(45)
+
OCMe
O
O
18 (31)
O
OCPh
O
OCPh
Me
3
Ph(CH2)2
Ph(CH2)2
SiMe3
14b
O
17b (99)
O
O
OCPh
Me
OCPh
4
6
Ph
Ph
SiMe3
16
O
19 (93)
a) Molar ratio [RhCl(CO)2]2:vinylsilane:(MeCO)2O = 0.05:1:3. The reaction was
conducted in toluene at 80 ꢁC. b) Isolated yield. c) The reaction was conducted at
ꢁ
100 C.
Table 6. Rh(I)-Catalyzed Acylation of (1-Benzoyloxy-
vinyl)silane 14b with Acid AnhydridesaÞ
Table 7. Conversion of ꢀ-Benzoyloxy Enones to ꢀ,ꢀ-
Dialkoxy Ketones and ꢀ-Diketones.
O
OCPh
O
OCPh
Me
5 mol% [RhCl(CO)2]2
(RCO)2O
O
OCPh
O
O
K2CO3
CF3COOH
CH2Cl2, rt
Me
Me
R
Ph(CH2)2
R'
R"
R"
Ph(CH2)2
ROH, rt
Toluene
SiMe3
RO OR
O
O
14b
17
O
Entry
R
Temp/ꢁC
Time/h
Yield/%
ROH
(Time)
ꢀ,ꢀ-Dialkoxy
ketone
Entry Enone
ꢀ-Diketone
1
2
3
4
5
6
7
Me
Me
Et
i-Pr
t-Bu
Ph
80
80
80
80
80
80
50
3
12
2
3
24
5
17b 99
17b 87bÞ
O
O
17c
99
Me
Me
MeOH
(5 min)
Ph(CH2)3
Ph(CH2)3
1
2
3
17b
17b
19
17d 97
MeO OMe
22a 92%
O
17e
17f
7cÞ
66dÞ
24 quant
O
CF3
4
17g (79)eÞ
Me
EtOH
(30 min)
Ph(CH2)3
a) Molar ratio [RhCl(CO)2]2:vinylsilane 14b:(RCO)2O =
0.05:1:3. b) 1.2 molar amounts of (MeCO)2O was used. c)
14b was recovered in 8% yield. d) Decarbonylation product
20 was obtained in 24% yield. e) Hydrate 21 was obtained
in 79% yield.
24 80%
EtO OEt
22b 95%
O
O
Ph
Me
Ph
Me
MeOH
(5 min)
O
O
OCPh
MeO OMe
CF3
O
Ph(CH2)3
23 99%
25 95%a)
Ph(CH2)2
Ph
HO OH
a) After FlorisilÒ column chromatography, the mixture of 25
and 26 were obtained in 1:1 ratio.
20
21
(Table 7, Entries 1 and 3) or ethanol (Entry 2).21,22 These ꢀ,ꢀ-
dialkoxy were readily transformed to ꢀ-diketones 24 and 25 by
dissolving in a 1:10 mixture of trifluoroacetic acid–dichloro-
methane (Table 7).22
OH
Ph
Me
26
O
Thus, the present rhodium-catalyzed acylation of (1-acyl-
oxyvinyl)silanes provided a preparative method of unsymmet-
rical ꢀ-diketones and also of ꢀ-acyloxy enones and ꢀ,ꢀ-di-
alkoxy ketones, which are regarded as regioselectively-masked
ꢀ-diketones at each of the carbonyl groups.
Experimental
1H NMR spectra were recorded with a Bruker
Avance 500 (500 MHz) and a Bruker DRX 500 (500 MHz) spec-
General.
trometer in CDCl3 [using CHCl3 (for 1H, ꢂ ¼ 7:24) as internal

M. Yamane et al.
Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
481
standard] or toluene-d8 [using C6D5CHD2 (for 1H, ꢂ ¼ 2:09) as
internal standard]. 13C NMR spectra were recorded with a Bruker
Avance 500 (125 MHz) and a Bruker DRX 500 (125 MHz) spec-
trometer in CDCl3 [using CDCl3 (for 13C, ꢂ ¼ 77:0) as internal
standard]. IR spectra were recorded on a Horiba FT 300-S by
ATR method. High resolution mass spectra were taken with a
JEOL MS-700M mass spectrometer. Melting points (mp) were un-
corrected. Elemental analyses were carried out at The Elemental
Analysis Laboratory, Department of Chemistry, Faculty of Sci-
ence, The University of Tokyo. Silica Gel 60 (spherical) (Kanto
Chemical) was used for column chromatography, and WakogelÒ
B-5F (Wako Pure Chemical Industries) was used for preparative
thin-layer chromatography. Toluene and 1,4-dioxane were freshly
distilled from lithium aluminium hydride before use. Tetrahydro-
furan (THF) was purchased in anhydrous form from Kanto Chem-
ical Co., Inc. Dichloromethane was distilled from phosphorus
pentoxide and calcium hydride, successively, and dried over MS
4A. Toluene-d8 (ACROS) and chloroform-d (Nippon Sanso) were
used as received. Acetic anhydride, propionic anhydride, and tri-
fluoroacetic anhydride were distilled from phosphorus pentoxide
before use. Benzoic anhydride was recrystallized from diethyl
ether. Acetic acid was distilled from KMnO4, and stored under ar-
gon. Hexamethylphosphoric triamide was distilled from calcium
hydride, dried over MS 4A, and stored under argon. Tetracarbon-
yldichlorodirhodium ([RhCl(CO)2]2) was prepared according to
the literature procedure.23
Preparation of Acylsilane 3 and (1-Methoxyvinyl)silane 4.
To a solution of LDA (0.339 mmol) in THF (2 mL) was added
1-dimethyl(phenyl)silyl-2-(2-phenylethynylphenyl)propan-1-one
(104 mg, 0.282 mmol) in THF (1 mL) at ꢂ78 ꢁC, and the solution
was stirred for 30 min at this temperature and at 0 ꢁC for an addi-
tional 1 h. After addition of MeI (200 mg, 1.41 mmol), the solu-
tion was stirred at room temperature. Then the solution was
quenched with saturated NH4Cl solution and the organic layer
was extracted with ethyl acetate. The combined organic extracts
were washed with water and dried over magnesium sulfate. After
evaporation of the solvent, the crude products were purified by
thin-layer chromatography (silica gel, hexane:diethyl ether =
15:1) to afford a 2:3 mixture of 1-dimethyl(phenyl)silyl-2-meth-
yl-2-(2-phenylethynylphenyl)propan-1-one (3) and (Z)-1-dimeth-
yl(phenyl)silyl-1-methoxy-2-(2-phenylethynylphenyl)prop-1-ene
(4) (88.4 mg, 0.231 mmol), in 82% total yield.
122.9, 123.0, 123.4, 126.4, 127.0, 127.1, 127.4, 127.5, 127.8,
128.1, 128.2, 128.3, 128.3, 128.6, 128.7, 129.0, 129.7, 130.9,
131.4, 131.4, 131.9, 133.7, 133.8, 133.8, 136.0, 138.6, 141.1,
144.0, 145.2, 158.0, 242.7; HRMS (FABþ) Found: m=z
383.1808. Calcd for C26H27OSi: (M + H)þ, 383.1831.
Rhodium-Catalyzed Reaction with Acylsilane 3 and (1-Me-
thoxyvinyl)silane 4. To a toluene solution (2.3 mL) of a 2:3 mix-
ture of 1-dimethyl(phenyl)silyl-2-methyl-2-(2-phenylethynylphen-
yl)propan-1-one (3) and (Z)-1-dimethyl(phenyl)silyl-1-methoxy-
2-(2-phenylethynylphenyl)prop-1-ene (4) (88.4 mg, 0.231 mmol)
was added [RhCl(CO)2]2 (4.8 mg, 0.012 mmol) and acetic acid
ꢁ
(139 mg, 2.31 mmol) and the mixture was heated at 100 C (the
oil bath temperature) for 12 h. After evaporation of the solvent,
the crude products were purified by thin-layer chromatography
(silica gel, hexane:diethyl ether = 8:1) to afford (E)-3-benzyl-
idene-1,1-dimethylindan-2-one (5) (15.4 mg, 0.062 mmol) in
73% yield based on 3 and (E)-1-benzylidene-2-methoxy-3-meth-
yl-1H-indene (6) (12.0 mg, 0.048 mmol) in 33% yield based on 4.
(E)-3-Benzylidene-1,1-dimethylindan-2-one (5): Yellow oil;
IR (ZnSe) 1726, 1622, 1092, 760, 696 cmꢂ1; 1H NMR (500 MHz,
CDCl3) ꢂ 1.38 (6H, s), 7.09–7.45 (6H, m), 7.55 (1H, s), 7.59–7.61
(2H, m), 7.69 (1 H, d, J ¼ 7:9 Hz); HRMS (FABþ) Found: m=z
249.1299. Calcd for C18H17O: (M + H)þ, 249.1279.
(E)-1-Benzylidene-2-methoxy-3-methyl-1H-indene
(6):
Yellow oil; IR (ZnSe) 1622, 1456, 1325, 1086, 754, 698 cmꢂ1
;
1H NMR (500 MHz, CDCl3) ꢂ 2.14 (3H, s), 3.95 (3H, s), 6.90
(1H, dd, J ¼ 7:3, 7.3 Hz), 7.08 (1H, d, J ¼ 7:3 Hz), 7.18 (1H,
dd, J ¼ 7:3, 7.3 Hz), 7.23 (1H, s), 7.36 (1H, d, J ¼ 7:3 Hz),
7.40–7.43 (3H, m), 7.55–7.56 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ 9.1, 61.6, 117.7, 119.5, 122.3, 124.1, 128.0, 128.0,
128.1, 128.3, 129.4, 130.0, 134.6, 136.5, 143.7, 155.1; HRMS
(FABþ) Found: m=z 249.1277. Calcd for C18H17O: (M + H)þ,
249.1279.
NMR Experiment in the Reaction of Vinylsilane 7a and
[RhCl(CO)2]2. Toluene-d8 solution (0.7 mL) of [RhCl(CO)2]2
(10.0 mg, 0.026 mmol), (E)-1-dimethyl(phenyl)silyl-4-phenyl-
but-1-ene (7a) (13.6 mg, 0.051 mmol), and mesitylene (5.3 mg,
ꢁ
0.044 mmol) in an NMR tube was heated at 80 C. The reaction
1
was followed by taking H NMR measurements every one hour.
After 10 h, the formation of chlorodimethyl(phenyl)silane (ꢂ ¼
0:43), dimethyl(phenyl)silanol (ꢂ ¼ 0:23), and 1,1,3,3-tetrameth-
yl-1,3-diphenyldisiloxane (ꢂ ¼ 0:31) was detected in 38%, 9%,
and 33% yields, respectively. Chemical shift values of products
were in good agreement with those of authentic samples,24 and
their yields were estimated based on mesitylene as internal
standard.
1-Dimethyl(phenyl)silyl-2-(2-phenylethynylphenyl)propan-
1-one: Colorless oil; IR (ZnSe) 1637, 1493, 1248, 1111, 816,
;
756, 690 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 0.24 (3H, s),
0.33 (3H, s), 1.24 (3H, d, J ¼ 6:8 Hz), 4.56 (1H, q, J ¼ 6:8
Hz), 6.81–6.82 (1H, m), 7.13–7.22 (4H, m), 7.27–7.30 (1H, m),
7.32–7.36 (5H, m), 7.45–7.48 (2H, m), 7.49–7.51 (1H, m);
13C NMR (125 MHz, CDCl3) ꢂ ꢂ4:3, ꢂ4:1, 15.9, 55.7, 87.7,
93.5, 123.1, 123.7, 126.9, 127.8, 128.4, 128.4, 128.4, 128.6,
129.5, 131.5, 132.7, 133.9, 134.7, 141.0, 243.2; Anal. Found: C,
81.33; H, 6.70%. Calcd for C25H24OSi: C, 81.47; H, 6.56%.
1-Dimethyl(phenyl)silyl-2-methyl-2-(2-phenylethynylphen-
yl)propan-1-one (3) and (Z)-1-Dimethyl(phenyl)silyl-1-me-
thoxy-2-(2-phenylethynylphenyl)prop-1-ene (4): These com-
pounds were obtained as a mixture (3:4 = 2:3). The stereo config-
uration of the alkene part of 4 is not determined. Colorless oil; IR
Typical Procedure for Preparation of Vinylsilane 7.25 To a
stirred solution of (E)-1-iodo-4-phenylbut-1-ene (1.53 g, 5.93
mmol) in THF/Et2O/pentane (14.4 mL, 4:1:1), cooled to ꢂ100
ꢁC, was added t-butyllithium (1.5 M in pentane, 8.0 mL, 11.9
mmol) over 10 min. The solution was stirred for 2 h at ꢂ100
ꢁ
ꢁC, and then allowed to warm to ꢂ78 C. Chlorodimethyl(phen-
yl)silane (1.22 g, 7.12 mmol) was added, and stirring was contin-
ued for 5 min at ꢂ78 ꢁC, and then for 45 min at room temperature.
The reaction mixture was poured on to diethyl ether and brine, and
the aqueous layer was extracted with diethyl ether. The combined
organic extracts were washed with brine and dried over magnesi-
um sulfate. The solvent was removed under reduced pressure, and
the residue was purified by column chromatography on silica gel
(hexane) to afford (E)-1-dimethyl(phenyl)silyl-4-phenylbut-1-ene
(7a) (1.35 g, 5.05 mmol) in 85% yield.
(ZnSe) 1635, 1493, 1246, 1111, 818, 754, 688 cmꢂ1 1H NMR
;
(500 MHz, CDCl3) 3 ꢂ 0.13 (6H, s), 1.37 (6H, s), 7.13–7.51
(14H, m); 4 ꢂ 0.05 (6H, brs), 2.09 (3H, s), 3.46 (3H, s), 7.01–
7.03 (1H, m), 7.13–7.51 (13H, m); 13C NMR (125 MHz, CDCl3)
ꢂ ꢂ3:1, ꢂ2:3, ꢂ1:9, 18.4, 23.5, 57.3, 59.4, 88.5, 89.0, 92.4, 94.4,
(E)-1-Dimethyl(phenyl)silyl-4-phenylbut-1-ene (7a): Color-

482 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Rhodium-Catalyzed Acylation of Vinylsilanes
less oil; IR (ZnSe) 1616, 1427, 1248, 1113, 841, 822, 698 cmꢂ1
;
128.2, 128.4, 128.8, 133.7, 139.6, 141.6, 149.6; HRMS (FABþ)
Found: m=z 267.1586. Calcd for C18H23Si: (M + H)þ, 267.1569.
(Z)-1-Dimethyl(phenyl)silyl-2-phenylethene (7f-cis)28 was
prepared according to the literature procedure;31 Colorless oil;
1H NMR (500 MHz, CDCl3) ꢂ 0.29 (6H, s), 2.42–2.47 (2H, m),
2.70–2.73 (2H, m), 5.76 (1H, dt, J ¼ 18:5, 1.5 Hz), 6.14 (1H,
dt, J ¼ 18:5, 6.2 Hz), 7.15–7.18 (3H, m), 7.24–7.27 (2H, m),
7.31–7.35 (3H, m), 7.44–7.48 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ ꢂ2:5, 35.1, 38.5, 125.8, 127.7, 128.2, 128.3, 128.5,
128.8, 133.8, 139.1, 141.8, 148.1; HRMS (FABþ) Found: m=z
267.1589. Calcd for C18H23Si: (M + H)þ, 267.1569.
IR (ZnSe) 1248, 1111, 810, 777, 696 cmꢂ1 1H NMR (500
;
MHz, CDCl3) ꢂ 0.25 (6H, s), 5.99 (1H, d, J ¼ 15:1 Hz), 7.17–
7.21 (5H, m), 7.31–7.35 (3H, m), 7.48 (1H, d, J ¼ 15:1 Hz),
7.52–7.55 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ ꢂ1:1, 127.5,
127.8, 127.8, 128.2, 128.8, 130.1, 133.7, 139.6, 139.6, 148.1.
Typical Procedure for Rhodium-Catalyzed Acylation of Vi-
nylsilane 7. To a 1,4-dioxane solution (9.3 mL) of (E)-1-dimeth-
yl(phenyl)silyl-4-phenylbut-1-ene (7a) (248 mg, 0.930 mmol) was
added [RhCl(CO)2]2 (18.1 mg, 0.047 mmol) and acetic anhydride
(284 mg, 2.79 mmol) and the mixture was heated at 90 ꢁC (the oil
bath temperature) for 7 h. After evaporation of the solvent, the
crude products were purified by thin-layer chromatography (silica
gel, hexane:ethyl acetate = 9:1) to afford (E)-6-phenylhex-3-en-2-
one (8a) (136 mg, 0.781 mmol) in 84% yield.
(E)-6-Phenylhex-3-en-2-one (8a):32 Colorless oil; IR (ZnSe)
1672, 1626, 1360, 1254, 976, 700 cmꢂ1 1H NMR (500 MHz,
;
CDCl3) ꢂ 2.21 (3H, s), 2.53 (2H, ddt, J ¼ 1:5, 6.8, 7.4 Hz),
2.77 (2H, t, J ¼ 7:4 Hz), 6.47 (1H, dt, J ¼ 16:0, 1.5 Hz), 6.80
(1H, dt, J ¼ 16:0, 6.8 Hz), 7.16–7.21 (3H, m), 7.27–7.30 (2H,
m); 13C NMR (125 MHz, CDCl3) ꢂ 26.8, 34.1, 34.3, 126.2,
128.3, 128.5, 131.6, 140.6, 147.1, 198.6.
(E)-4-Phenyl-1-trimethylsilylbut-1-ene (7b):26 Colorless oil;
1
IR (ZnSe) 2954, 1616, 1246, 864, 833, 696 cmꢂ1; H NMR (500
MHz, CDCl3) ꢂ 0.02 (9H, s), 2.37–2.42 (2H, m), 2.68–2.71 (2H,
m), 5.65 (1H, dt, J ¼ 18:6, 1.4 Hz), 6.06 (1H, dt, J ¼ 18:6, 6.1
Hz), 7.15–7.18 (3H, m), 7.23–7.27 (2H, m); 13C NMR (125
MHz, CDCl3) ꢂ ꢂ1:2, 35.2, 38.5, 125.7, 128.2, 128.4, 130.4,
142.0, 146.1.
(E)-1-Methyldiphenylsilyl-4-phenylbut-1-ene (7c):27 Color-
less oil; IR (ZnSe) 1614, 1427, 1250, 1111, 791, 733, 696 cmꢂ1
1H NMR (500 MHz, CDCl3) ꢂ 0.57 (3H, s), 2.50 (2H, ddt,
J ¼ 1:4, 6.2, 7.4 Hz), 2.74 (2H, t, J ¼ 7:4 Hz), 5.94 (1H, dt,
J ¼ 18:5, 1.4 Hz), 6.16 (1H, dt, J ¼ 18:5, 6.2 Hz), 7.15–7.20
(3H, m), 7.24–7.28 (2H, m), 7.31–7.38 (6H, m), 7.45–7.47 (4H,
m); 13C NMR (125 MHz, CDCl3) ꢂ ꢂ3:7, 34.9, 38.5, 125.8,
126.2, 127.7, 128.3, 128.5, 129.1, 134.8, 136.8, 141.6, 150.2;
HRMS (EIþ) Found: m=z 328.1621. Calcd for C23H24Si: Mþ,
328.1647.
;
(E)-4-Phenyl-1-triphenylsilylbut-1-ene (7d): Colorless oil;
1H NMR
(E)-7-Phenylhept-4-en-3-one (8b): Colorless oil; IR (ZnSe)
IR (ZnSe) 1616, 1427, 1109, 997, 737, 698 cmꢂ1
;
1697, 1672, 1630, 1496, 1454, 1358, 1201, 976, 700 cmꢂ1
;
(500 MHz, CDCl3) ꢂ 2.53–2.57 (2H, m), 2.73–2.77 (2H, m),
6.13–6.22 (2H, m), 7.14–7.20 (3H, m), 7.22–7.29 (3H, m),
7.31–7.35 (6H, m), 7.37–7.41 (3H, m), 7.45–7.47 (5H, m);
13C NMR (125 MHz, CDCl3) ꢂ 34.9, 38.6, 124.4, 125.8, 127.8,
128.3, 128.5, 129.4, 134.8, 135.9, 141.6, 152.2; Anal. Found: C,
85.97; H, 6.83%. Calcd for C28H26Si: C, 86.10; H, 6.71%.
(E)-1-Dimethyl(phenyl)silyl-2-phenylethylene (7f):28 Color-
less oil; IR (ZnSe) 1604, 1574, 1495, 1427, 1248, 1113, 989, 829,
1H NMR (500 MHz, CDCl3) ꢂ 1.07 (3H, t, J ¼ 7:3 Hz), 2.49–
2.54 (4H, m), 2.77 (2H, t, J ¼ 7:4 Hz), 6.10 (1H, dt, J ¼ 15:9,
1.5 Hz), 6.83 (1H, dt, J ¼ 15:9, 6.8 Hz), 7.15–7.20 (3H, m),
7.26–7.29 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 8.1, 33.2,
34.1, 34.4, 126.2, 128.3, 128.5, 130.5, 140.7, 145.6, 201.0; HRMS
(FABþ) Found: m=z 189.1282. Calcd for C13H17O: (M + H)þ,
189.1279.
(E)-2-Methyl-7-phenylhept-4-en-3-one (8c): Colorless oil;
IR (ZnSe) 1695, 1670, 1626, 1456, 1383, 1207, 980, 698 cmꢂ1
;
1
698 cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 0.42 (6H, s), 6.58 (1H,
d, J ¼ 19:1 Hz), 6.93 (1H, d, J ¼ 19:1 Hz), 7.23–7.37 (6H, m),
7.43–7.44 (2H, m), 7.55–7.57 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ ꢂ2:5, 126.5, 127.0, 127.8, 128.1, 128.5, 129.0, 133.9,
138.1, 138.5, 145.3.
1H NMR (500 MHz, CDCl3) ꢂ 1.07 (6H, d, J ¼ 6:9 Hz), 2.50–
2.54 (2H, m), 2.75–2.79 (2H, m), 2.77 (1H, sep, J ¼ 6:9 Hz),
6.15 (1H, dt, J ¼ 15:7, 1.5 Hz), 6.88 (1H, dt, J ¼ 15:7, 6.9 Hz),
7.15–7.20 (3H, m), 7.25–7.29 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ 18.4, 34.1, 34.5, 38.5, 126.1, 128.3, 128.4, 128.8,
140.8, 145.7, 203.9; HRMS (FABþ) Found: m=z 203.1437. Calcd
for C14H19O: (M + H)þ, 203.1436.
1-Dimethyl(phenyl)silylcyclopentene (7g):29 Colorless oil;
IR (ZnSe) 2954, 1250, 1111, 1057, 827, 795, 771, 698 cmꢂ1
;
1H NMR (500 MHz, CDCl3) ꢂ 0.34 (6H, s), 1.81 (2H, quint, J ¼
7:5 Hz), 2.34–2.40 (4H, m), 6.04–6.06 (1H, m), 7.32–7.35 (3H,
m), 7.48–7.51 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ ꢂ3:0,
24.1, 35.0, 36.0, 127.7, 128.8, 133.8, 138.8, 142.4, 142.6.
(E)-1-Dimethyl(phenyl)silylbuta-1,3-diene (7i):30 Colorless
oil; IR (ZnSe) 1572, 1427, 1248, 1113, 1011, 833, 812, 729,
(E)-2,2-Dimethyl-7-phenylhept-4-en-3-one (8d): Colorless
oil; IR (ZnSe) 1689, 1624, 1477, 1456, 1078, 698 cmꢂ1; 1H NMR
(500 MHz, CDCl3) ꢂ 1.10 (9H, s), 2.48–2.53 (2H, m), 2.74–2.77
(2H, m), 6.44 (1H, dt, J ¼ 15:3, 7.0 Hz), 6.94 (1H, dt, J ¼ 15:3,
1.5 Hz), 7.15–7.19 (3H, m), 7.25–7.28 (2H, m); 13C NMR (125
MHz, CDCl3) ꢂ 26.1, 34.2, 34.5, 42.8, 124.8, 126.0, 128.3,
128.4, 140.9, 146.0, 204.2; HRMS (FABþ) Found: m=z
217.1584. Calcd for C15H21O: (M + H)þ, 217.1592.
698 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 0.36 (6H, s), 5.14
;
(1H, dd, J ¼ 1:6, 10.0 Hz), 5.24 (1H, dd, J ¼ 1:6, 17.0 Hz),
5.99 (1H, dd, J ¼ 0:6, 18.3 Hz), 6.38 (1H, ddt, J ¼ 0:6, 17.0,
10.0 Hz), 6.58 (1H, dd, J ¼ 10:0, 18.3 Hz), 7.33–7.37 (3H, m),
7.50–7.54 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ ꢂ2:6, 118.2,
127.8, 129.0, 132.3, 133.8, 138.5, 139.7, 146.2.
(Z)-1-Dimethyl(phenyl)silyl-4-phenylbut-1-ene (7a-cis) was
prepared according to the literature procedure;31 Colorless oil;
IR (ZnSe) 2956, 1604, 1248, 1111, 818, 698 cmꢂ1 1H NMR
;
(500 MHz, CDCl3) ꢂ 0.33 (6H, s), 2.30–2.35 (2H, m), 2.54–
2.57 (2H, m), 5.66 (1H, dt, J ¼ 14:0, 1.2 Hz), 6.45 (1H, dt,
J ¼ 14:0, 7.4 Hz), 7.00–7.02 (2H, m), 7.13–7.16 (1H, m), 7.20–
7.23 (2H, m), 7.31–7.34 (3H, m), 7.50–7.53 (2H, m); 13C NMR
(125 MHz, CDCl3) ꢂ ꢂ0:9, 35.7, 35.7, 125.8, 127.5, 127.8,
(E)-1,5-Diphenylpent-2-en-1-one (8e):32 Colorless oil; IR
;
(ZnSe) 1668, 1618, 1446, 1282, 980, 694 cmꢂ1 1H NMR (500
MHz, CDCl3) ꢂ 2.64 (2H, ddt, J ¼ 1:4, 6.9, 7.4 Hz), 2.84 (2H,
t, J ¼ 7:4 Hz), 6.85 (1H, dt, J ¼ 15:4, 1.4 Hz), 7.07 (1H, dt,
J ¼ 15:4, 6.9 Hz), 7.19–7.22 (3H, m), 7.27–7.31 (2H, m), 7.43–
7.46 (2H, m), 7.52–7.56 (1H, m), 7.86–7.88 (2H, m); 13C NMR
(125 MHz, CDCl3) ꢂ 34.5, 34.5, 126.2, 126.5, 128.4, 128.4,
128.5, 128.5, 132.6, 137.8, 140.8, 148.4, 190.8.
(E)-1,4-Diphenylbut-1-ene (9):32 Colorless oil; IR (ZnSe)
1496, 1456, 1448, 1030, 962, 739, 696 cmꢂ1 1H NMR (500
;
MHz, CDCl3) ꢂ 2.49–2.54 (2H, m), 2.76–2.79 (2H, m), 6.24

M. Yamane et al.
Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
483
ꢁ
(1H, dt, J ¼ 15:8, 6.8 Hz), 6.40 (1H, dt, J ¼ 15:8, 1.3 Hz), 7.16–
7.21 (4H, m), 7.25–7.32 (6H, m); 13C NMR (125 MHz, CDCl3) ꢂ
34.9, 35.9, 125.9, 126.0, 126.9, 128.3, 128.5, 128.5, 130.0, 130.4,
137.7, 141.8.
4.81 mmol), the solution was kept at ꢂ78 C for 5 min and then
at room temperature for an additional 1 h. Then the solution was
quenched with saturated NH4Cl solution and the organic layer was
extracted with ethyl acetate. The combined organic extracts were
washed with water and dried over magnesium sulfate. The solvent
was removed under reduced pressure, and the obtained residue
was dissolved in 20 mL of 80% acetic acid and the solution was
heated at 80 ꢁC for 30 min. After cooling, the solution was extract-
ed with diethyl ether, and the combined extracts were washed with
brine and dried over magnesium sulfate. The solvent was removed
under reduced pressure, and the residue was purified by column
chromatography on silica gel (hexane–ethyl acetate 50:1) to afford
4-phenyl-1-trimethylsilylbutan-1-one (13a) in 55% yield (2 steps).
4-Phenyl-1-trimethylsilylbutan-1-one (13a): Colorless oil;
IR (ZnSe) 1641, 1496, 1454, 1248, 839, 739, 698 cmꢂ1; 1H NMR
(500 MHz, CDCl3) ꢂ 0.16 (9H, s), 1.83 (2H, tt, J ¼ 7:2, 7.4 Hz),
2.57 (2H, t, J ¼ 7:4 Hz), 2.60 (2H, t, J ¼ 7:2 Hz), 7.13–7.18 (3H,
m), 7.24–7.27 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ ꢂ3:3,
23.6, 35.1, 47.5, 125.8, 128.2, 128.4, 141.8, 248.0; Anal. Found:
C, 70.78; H, 9.12%. Calcd for C13H20OSi: C, 70.85; H, 9.15%.
2-Phenyl-1-trimethylsilylethanone (13b): Colorless oil; IR
(E)-4-Phenylbut-3-en-2-one (Benzylideneacetone) (8f):33
White crystals; mp 59–60 ꢁC; IR (ZnSe) 1666, 1608, 1358,
1255, 974, 748, 690 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 2.37
;
(3H, s), 6.70 (1H, d, J ¼ 16:3 Hz), 7.37–7.40 (3H, m), 7.50
(1H, d, J ¼ 16:3 Hz), 7.52–7.55 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ 27.3, 126.9, 128.1, 128.8, 130.3, 134.2, 143.2, 198.1.
Cyclopent-1-en-1-yl Phenyl Ketone (8g):34 Colorless oil; IR
1
(ZnSe) 1637, 1608, 1446, 1354, 1296, 1273, 708 cmꢂ1; H NMR
(500 MHz, CDCl3) ꢂ 1.96–2.02 (2H, m), 2.58–2.62 (2H, m), 2.70–
2.75 (2H, m), 6.51–6.53 (1H, m), 7.39–7.42 (2H, m), 7.48–7.51
(1H, m), 7.70–7.72 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ
22.8, 31.8, 34.3, 128.1, 128.8, 131.7, 139.0, 144.5, 146.9, 194.2.
1-Phenylprop-2-en-1-one (8h):35 Colorless oil; IR (ZnSe)
1672, 1608, 1448, 1404, 1232, 993, 727 cmꢂ1 1H NMR (500
;
MHz, CDCl3) ꢂ 5.92 (1H, dd, J ¼ 1:6, 10.6 Hz), 6.42 (1H, dd,
J ¼ 1:6, 17.1 Hz), 7.14 (1H, dd, J ¼ 10:6, 17.1 Hz), 7.45–7.48
(2H, m), 7.54–7.58 (1H, m), 7.92–7.94 (2H, m); 13C NMR (125
MHz, CDCl3) ꢂ 128.6, 128.7, 130.2, 132.4, 133.0, 137.3, 191.1.
1-Phenylpent-4-en-1-one (10):36 Colorless oil; IR (ZnSe)
(ZnSe) 1651, 1635, 1250, 845, 748, 702 cmꢂ1 1H NMR (500
;
MHz, CDCl3) ꢂ 0.09 (9H, s), 3.83 (2H, s), 7.10–7.12 (2H, m),
7.21–7.24 (1H, m), 7.28–7.31 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ ꢂ2:8, 55.5, 126.8, 128.6, 129.9, 133.1, 244.2; Anal.
Found: C, 68.49; H, 8.31%. Calcd for C11H16OSi: C, 68.69; H,
8.39%.
Typical Procedure for Preparation of (1-Acyloxyvinyl)-
silane 14–16. To a solution of LDA (5.51 mmol) in THF 20
mL was added hexamethylphosphoric triamide (8.98 g, 50.1
1
1730, 1685, 1448, 1325, 1273, 1128 cmꢂ1; H NMR (500 MHz,
CDCl3) ꢂ 2.46–2.51 (2H, m), 3.06 (2H, t, J ¼ 7:4 Hz), 5.00
(1H, dd, J ¼ 1:5, 10.3 Hz), 5.07 (1H, dd, J ¼ 1:5, 17.1 Hz),
5.89 (1H, ddt, J ¼ 10:3, 17.1, 6.5 Hz), 7.43–7.46 (2H, m),
7.53–7.58 (1H, m), 7.94–7.96 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ 28.1, 37.7, 115.3, 128.0, 128.6, 133.0, 136.9, 137.3,
199.4.
(E)-1-Phenylpenta-2,4-dien-1-one (8i):37
Yellow oil; IR
mmol) at ꢂ78 C, and the solution was stirred for 5 min at this
ꢁ
(ZnSe) 1662, 1587, 1448, 1273, 1219, 1016, 688 cmꢂ1; H NMR
(500 MHz, CDCl3) ꢂ 5.57 (1H, dd, J ¼ 0:6, 10.2 Hz), 5.70 (1H,
dd, J ¼ 0:6, 16.9 Hz), 6.58 (1H, ddt, J ¼ 0:5, 16.9, 10.2 Hz),
6.98 (1H, dd, J ¼ 0:5, 15.1 Hz), 7.38 (1H, dd, J ¼ 10:2, 15.1
Hz), 7.44–7.47 (2H, m), 7.53–7.56 (1H, m), 7.92–7.94 (2H, m);
13C NMR (125 MHz, CDCl3) ꢂ 126.2, 126.8, 128.4, 128.6,
132.7, 135.4, 137.9, 144.7, 190.7.
temperature. THF (5 mL) solution of 4-phenyl-1-trimethylsilyl-
butan-1-one (13a) (1.10 g, 5.01 mmol) was added, and the mixture
was stirred at this temperature for 2 h. After addition of benzoic
1
ꢁ
anhydride (1.70 g, 7.51 mmol), the solution was kept at ꢂ78 C
for 5 min and then at room temperature for an additional 1 h. Then
the solution was quenched with saturated NH4Cl solution and the
organic layer was extracted with ethyl acetate. The combined or-
ganic extracts were washed with water and dried over magnesium
sulfate. The solvent was removed under reduced pressure, and the
residue was purified by column chromatography on silica gel
(hexane:ethyl acetate = 50:1) to afford (E)-4-phenyl-1-trimethyl-
silylbut-1-en-1-yl benzoate (14b) in 86% yield.
6-Phenylhex-4-en-2-one (11-trans and 11-cis):38 11-trans,
11-cis, and 8a were obtained as a mixture (11-trans:11-cis:8a =
53:10:37). Their yields were estimated by allylic proton ratios
1
1
of H NMR. Colorless oil; H NMR (500 MHz, CDCl3) 11-trans
ꢂ 2.14 (3H, s), 3.14 (2H, d, J ¼ 6:7 Hz), 3.38 (2H, d, J ¼ 6:5
Hz), 5.59–5.73 (2H, m), 7.16–7.30 (5H, m); 11-cis ꢂ 2.17 (3H,
s), 3.28 (2H, d, J ¼ 7:3 Hz), 3.37–3.40 (2H, m), 5.77–5.83 (2H,
m), 7.16–7.30 (5H, m).
(E)-4-Phenyl-1-trimethylsilylbut-1-en-1-yl Acetate (14a):
Colorless oil; IR (ZnSe) 1743, 1369, 1219, 839, 771, 698 cmꢂ1
;
1H NMR (500 MHz, CDCl3) ꢂ 0.10 (9H, s), 2.11 (3H, s), 2.30–
2.34 (2H, m), 2.63–2.67 (2H, m), 5.49 (1H, t, J ¼ 7:0 Hz),
7.15–7.19 (3H, m), 7.25–7.28 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ ꢂ1:5, 20.6, 27.6, 35.0, 125.9, 128.3, 128.4, 130.5,
141.6, 155.3, 169.2; Anal. Found: C, 68.46; H, 8.42%. Calcd for
C15H22O2Si: C, 68.65; H, 8.45%.
(E,E)-6-Phenylhexa-3,5-dien-2-one (12):39 Colorless oil; IR
(ZnSe) 1653, 1614, 1587, 997, 881, 827, 690 cmꢂ1; 1H NMR (500
MHz, CDCl3) ꢂ 2.30 (3H, s), 6.24 (1H, d, J ¼ 15:5 Hz), 6.87 (1H,
dd, J ¼ 10:4, 15.6 Hz), 6.94 (1H, d, J ¼ 15:6 Hz), 7.28 (1H, dd,
J ¼ 10:4, 15.5 Hz), 7.29–7.37 (3H, m), 7.45–7.47 (2H, m);
13C NMR (125 MHz, CDCl3) ꢂ 27.4, 126.2, 127.2, 128.8, 129.2,
130.5, 135.9, 141.3, 143.5, 198.5.
Typical Procedure for Preparation of Acylsilane 13. The
preparation in the literature was slightly modified.40 To a solution
of 1-(phenoxymethyl)benzotriazole (1.20 g, 5.34 mmol) in THF
(75 mL) at ꢂ78 ꢁC was added butyllithium (1.57 M in hexane,
3.4 mL, 5.34 mmol) and the solution was stirred for 5 min at this
temperature. Chlorotrimethylsilane (580 mg, 5.34 mmol) was add-
ed, and the mixture was stirred at this temperature for 15 min, add-
ing a second portion of butyllithium (1.57 M in hexane, 3.4 mL,
5.34 mmol). After addition of 3-phenylpropyl bromide (957 mg,
(Z)-4-Phenyl-1-trimethylsilylbut-1-en-1-yl Acetate (15):
Colorless oil; IR (ZnSe) 1738, 1367, 1232, 1047, 839, 698
cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 0.16 (9H, s), 2.09 (3H, s),
2.39–2.44 (2H, m), 2.67–2.70 (2H, m), 5.85 (1H, t, J ¼ 8:2 Hz),
7.17–7.21 (3H, m), 7.27–7.30 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ ꢂ1:0, 20.8, 29.6, 36.1, 126.0, 128.4, 128.4, 133.3,
141.1, 154.9, 170.6.
(E)-4-Phenyl-1-trimethylsilylbut-1-en-1-yl Benzoate (14b):
Colorless oil; IR (ZnSe) 1720, 1452, 1263, 1246, 1095, 839,
706 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 0.17 (9H, s), 2.42
;
(2H, dt, J ¼ 7:1, 7.5 Hz), 2.71 (2H, t, J ¼ 7:5 Hz), 5.61 (1H, t,
1

484 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Rhodium-Catalyzed Acylation of Vinylsilanes
J ¼ 7:1 Hz), 7.15–7.18 (3H, m), 7.24–7.27 (2H, m), 7.44–7.47
(2H, m), 7.56–7.59 (1H, m), 8.05–8.07 (2H, m); 13C NMR (125
MHz, CDCl3) ꢂ ꢂ1:3, 27.7, 35.1, 125.9, 128.3, 128.4, 128.4,
129.8, 130.0, 130.7, 133.0, 141.6, 155.6, 164.8; Anal. Found: C,
74.05; H, 7.49%. Calcd for C20H24O2Si: C, 74.03; H, 7.45%.
(E)-2-Phenyl-1-trimethylsilylvinyl Benzoate (16): Colorless
oil; IR (ZnSe) 1720, 1282, 1243, 1105, 1093, 1068, 841, 708, 692
m), 8.11–8.13 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 7.9,
27.8, 30.6, 34.2, 126.2, 128.3, 128.5, 128.5, 128.7, 130.2, 130.3,
133.7, 140.5, 146.1, 164.3, 194.4; Anal. Found: C, 77.90; H,
6.74%. Calcd for C20H20O3: C, 77.90; H, 6.54%.
(Z)-2-Methyl-3-oxo-7-phenylhept-4-en-4-yl Benzoate (17d):
Colorless oil; IR (ZnSe) 1734, 1684, 1452, 1240, 1084, 1063,
1
1024, 700 cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 1.14 (6H, d, J ¼
1
cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 0.26 (9H, s), 6.36 (1H, s),
6:8 Hz), 2.58 (2H, dt, J ¼ 7:5, 7.5 Hz), 2.81 (2H, t, J ¼ 7:5 Hz),
3.09 (1H, sep, J ¼ 6:8 Hz), 6.57 (1H, t, J ¼ 7:5 Hz), 7.17–7.22
(3H, m), 7.26–7.29 (2H, m), 7.46–7.49 (2H, m), 7.59–7.63 (1H,
m), 8.10–8.12 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 18.9,
27.9, 34.3, 34.8, 126.3, 128.3, 128.5, 128.5, 128.7, 130.2, 130.4,
133.6, 140.5, 145.5, 164.3, 197.9; Anal. Found: C, 78.22; H,
7.04%. Calcd for C21H22O3: C, 78.23; H, 6.88%.
7.17–7.20 (1H, m), 7.24–7.27 (2H, m), 7.47–7.50 (4H, m),
7.59–7.62 (1H, m), 8.11–8.13 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ ꢂ0:9, 127.6, 128.3, 128.4, 128.6, 129.1, 129.7, 130.0,
133.2, 134.3, 156.6, 164.9; Anal. Found: C, 72.92; H, 6.90%.
Calcd for C18H20O2Si: C, 72.93; H, 6.80%.
Typical Procedure for Rhodium-Catalyzed Acylation of (1-
Acyloxyvinyl)silane 14–16. To a toluene solution (6.8 mL) of
(E)-4-phenyl-1-trimethylsilylbut-1-en-1-yl benzoate (14b) (222
mg, 0.684 mmol) was added [RhCl(CO)2]2 (13.8 mg, 0.035
mmol) and acetic anhydride (209 mg, 2.05 mmol) and the mixture
was heated at 80 ꢁC (the oil bath temperature) for 3 h. After evap-
oration of the solvent, the crude products were purified by thin-
layer chromatography (silica gel, hexane:ethyl acetate = 5:1) to
afford (Z)-2-oxo-6-phenylhex-3-en-3-yl benzoate (17b) (199 mg,
0.675 mmol) in 99% yield.
(Z)-2,2-Dimethyl-3-oxo-7-phenylhept-4-en-4-yl
(17e): Colorless oil; IR (ZnSe) 1734, 1684, 1456, 1259, 1082,
1066, 706 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 1.22 (9H, s),
Benzoate
;
2.49 (2H, dt, J ¼ 7:5, 7.5 Hz), 2.77 (2H, t, J ¼ 7:5 Hz), 6.43
(1H, t, J ¼ 7:5 Hz), 7.14–7.17 (3H, m), 7.24–7.27 (2H, m),
7.46–7.49 (2H, m), 7.59–7.62 (1H, m), 8.07–8.09 (2H, m);
13C NMR (125 MHz, CDCl3) ꢂ 27.6, 28.0, 34.3, 43.0, 126.2,
128.4, 128.5, 128.6, 128.8, 129.8, 130.2, 133.7, 140.6, 144.7,
164.2, 200.0; HRMS (FABþ) Found: m=z 337.1831. Calcd for
C22H25O3: (M + H)þ, 337.1804.
(Z)-2-Oxo-6-phenylhex-3-en-3-yl Acetate (17a): Colorless
oil; IR (ZnSe) 1761, 1685, 1371, 1205, 1099, 771, 700 cmꢂ1
;
(Z)-1-Oxo-1,5-diphenylpent-2-en-2-yl Benzoate (17f): Col-
orless oil; IR (ZnSe) 1732, 1662, 1599, 1452, 1259, 1128, 1063,
1H NMR (500 MHz, CDCl3) ꢂ 2.23 (3H, s), 2.26 (3H, s), 2.49
(2H, dt, J ¼ 7:4, 7.5 Hz), 2.76 (2H, t, J ¼ 7:5 Hz), 6.43 (1H, t,
J ¼ 7:4 Hz), 7.16–7.22 (3H, m), 7.27–7.31 (2H, m); 13C NMR
(125 MHz, CDCl3) ꢂ 20.2, 25.1, 27.8, 34.2, 126.3, 128.2, 128.5,
131.5, 140.4, 146.4, 168.5, 191.2; Anal. Found: C, 72.23; H,
7.11%. Calcd for C14H16O3: C, 72.39; H, 6.94%.
1
706 cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 2.68 (2H, dt, J ¼ 7:4,
7.4 Hz), 2.82 (2H, t, J ¼ 7:4 Hz), 6.22 (1H, t, J ¼ 7:4 Hz),
7.17–7.22 (3H, m), 7.27–7.30 (2H, m), 7.39–7.42 (2H, m),
7.46–7.54 (3H, m), 7.57–7.63 (1H, m), 7.75–7.77 (2H, m),
8.11–8.12 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 28.0, 34.4,
126.3, 128.2, 128.4, 128.5, 128.5, 128.6, 129.4, 130.2, 132.4,
133.1, 133.7, 136.8, 140.5, 146.1, 164.3, 189.7; Anal. Found: C,
80.78; H, 5.78%. Calcd for C24H20O3: C, 80.88; H, 5.66%.
(Z)-1,4-Diphenylbut-1-en-1-yl Benzoate (20): Colorless oil;
(E)-2-Oxo-6-phenylhex-3-en-3-yl Acetate (18):
Colorless
oil; IR (ZnSe) 1755, 1699, 1365, 1209, 1095, 700 cmꢂ1; 1H NMR
(500 MHz, CDCl3) ꢂ 2.12 (3H, s), 2.19 (3H, s), 2.75 (2H, t, J ¼
7:5 Hz), 2.84–2.89 (2H, m), 5.75 (1H, t, J ¼ 7:8 Hz), 7.17–7.19
(3H, m), 7.26–7.29 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ
20.7, 27.7, 28.5, 35.1, 126.1, 128.4, 128.5, 131.8, 140.7, 144.2,
170.0, 194.5.
IR (ZnSe) 1732, 1495, 1450, 1240, 1088, 1066, 1026, 708 cmꢂ1
;
1H NMR (500 MHz, CDCl3) ꢂ 2.52 (2H, dt, J ¼ 7:3, 7.5 Hz), 2.82
(2H, t, J ¼ 7:5 Hz), 5.98 (1H, t, J ¼ 7:3 Hz), 7.19–7.22 (3H, m),
7.27–7.33 (5H, m), 7.44–7.48 (2H, m), 7.51–7.54 (2H, m), 7.63–
7.66 (1H, m), 8.19–8.21 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ
28.0, 35.1, 117.2, 124.4, 125.9, 128.2, 128.3, 128.4, 128.5, 128.6,
129.2, 130.1, 133.6, 134.9, 141.4, 146.6, 164.3; HRMS (FABþ)
Found: m=z 329.1555. Calcd for C23H21O2: (M + H)þ, 329.1542.
(Z)-2-Oxo-6-phenylhex-3-en-3-yl Benzoate (17b): Colorless
oil; IR (ZnSe) 1734, 1685, 1452, 1246, 1088, 1068, 1024, 771,
;
704 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 2.32 (3H, s), 2.56
(2H, dt, J ¼ 7:5, 7.5 Hz), 2.80 (2H, t, J ¼ 7:5 Hz), 6.57 (1H, t,
J ¼ 7:5 Hz), 7.16–7.22 (3H, m), 7.26–7.29 (2H, m), 7.46–7.49
(2H, m), 7.60–7.63 (1H, m), 8.10–8.12 (2H, m); 13C NMR (125
MHz, CDCl3) ꢂ 25.3, 27.9, 34.2, 126.3, 128.3, 128.5, 128.5,
128.6, 130.2, 131.5, 133.7, 140.4, 146.5, 164.2, 191.3; Anal.
Found: C, 77.45; H, 6.22%. Calcd for C19H18O3: C, 77.53; H,
6.16%.
1,1,1-Trifluoro-2,2-dihydroxy-6-phenylhexan-3-one
White crystals; mp 69–72 ꢁC; IR (ZnSe) 1732, 1496, 1456,
1165, 1103, 1066, 746, 700 cmꢂ1 1H NMR (500 MHz, CDCl3)
(21):
;
ꢂ 1.99 (2H, tt, J ¼ 7:1, 7.4 Hz), 2.64 (2H, t, J ¼ 7:4 Hz), 2.84
(2H, t, J ¼ 7:1 Hz), 4.46 (2H, s), 7.12–7.21 (3H, m), 7.27–7.30
(Z)-3-Oxo-1-phenylbut-1-en-2-yl Benzoate (19):
crystal; mp 81–82 ꢁC; IR (ZnSe) 1734, 1682, 1244, 1088, 708,
690 cmꢂ1 1H NMR (500 MHz, CDCl3) ꢂ 2.47 (3H, s), 7.28
White
(2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 24.6, 34.7, 35.4 (q, JCF
2 Hz), 92.1 (q, JCF ¼ 34 Hz), 121.4 (q, JCF ¼ 287 Hz), 126.2,
128.4, 128.5, 141.0, 202.5; HRMS (FABþ) Found: m=z
263.0914. Calcd for C12H14O3F3: (M + H)þ, 263.0895.
¼
;
(1H, s), 7.32–7.34 (3H, m), 7.50–7.53 (2H, m), 7.58–7.67 (3H,
m), 8.18–8.20 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 25.4,
128.0, 128.6, 128.7, 128.8, 130.1, 130.3, 130.3, 131.9, 133.9,
144.7, 164.2, 192.1; Anal. Found: C, 76.76; H, 5.44%. Calcd for
C17H14O3: C, 76.68; H, 5.30%.
Typical Procedure for Preparation of ꢀ,ꢀ-Dialkoxy Ketone
(22, 23). To a methanol solution (3 mL) of potassium carbonate
(494 mg, 3.57 mmol) was added (Z)-2-oxo-6-phenylhex-3-en-3-yl
benzoate (17b) (105 mg, 0.357 mmol) in methanol (1 mL) at room
temperature and the solution was stirred at this temperature for 5
min. Then the solution was quenched with water and the organic
layer was extracted three times with diethyl ether. The combined
organic extracts were dried over magnesium sulfate. The solvent
was removed under reduced pressure, and the residue was purified
by column chromatography on FlorisilÒ (hexane:ethyl acetate =
(Z)-3-Oxo-7-phenylhept-4-en-4-yl Benzoate (17c): Color-
less oil; IR (ZnSe) 1734, 1687, 1452, 1244, 1219, 1090, 771,
708 cmꢂ1
;
1H NMR (500 MHz, CDCl3) ꢂ 1.11 (3H, t, J ¼ 7:3
Hz), 2.55 (2H, dt, J ¼ 7:5, 7.5 Hz), 2.66 (2H, q, J ¼ 7:3 Hz),
2.80 (2H, t, J ¼ 7:5 Hz), 6.57 (1H, t, J ¼ 7:5 Hz), 7.16–7.21
(3H, m), 7.26–7.29 (2H, m), 7.46–7.49 (2H, m), 7.60–7.63 (1H,

M. Yamane et al.
Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
485
5:1) to afford 2,2-dimethoxy-6-phenylhexan-3-one (22a) (77.5
mg, 0.328 mmol) in 92% yield.
mmol) was added acetyl chloride (31.2 mg, 0.40 mmol) and alu-
minium chloride (52.9 mg, 0.40 mmol), successively, and the so-
lution was stirred at room temperature for 24 h. Then the solution
was quenched with saturated NaHCO3 solution and the organic
layer was extracted twice with dichloromethane. The combined
organic extracts were washed with brine and dried over magnesi-
um sulfate. The solvent was removed under reduced pressure and
the crude products were purified by thin-layer chromatography
(silica gel, hexane:ethyl acetate = 4:1) to afford (E)-4-(4-acetyl-
phenyl)-1-trimethylsilylbut-1-en-1-yl benzoate (27) (54.1 mg,
0.15 mmol) in 74% yield.
2,2-Dimethoxy-6-phenylhexan-3-one (22a): Colorless oil; IR
(ZnSe) 2941, 1726, 1496, 1454, 1367, 1149, 1045 cmꢂ1; 1H NMR
(500 MHz, CDCl3) ꢂ 1.32 (3H, s), 1.90 (2H, tt, J ¼ 7:4, 7.4 Hz),
2.59 (2H, t, J ¼ 7:4 Hz), 2.61 (2H, t, J ¼ 7:4 Hz), 3.19 (6H, s),
7.14–7.19 (3H, m), 7.23–7.28 (2H, m); 13C NMR (125 MHz,
CDCl3) ꢂ 19.8, 24.8, 35.1, 37.2, 49.7, 102.6, 125.9, 128.3,
128.4, 141.7, 209.0; HRMS (FABþ) Found: m=z 237.1495. Calcd
for C14H21O3: (M + H)þ, 237.1491.
2,2-Diethoxy-6-phenylhexan-3-one (22b): Colorless oil; IR
1
(ZnSe) 1728, 1454, 1173, 1144, 1097, 958, 700 cmꢂ1; H NMR
(E)-4-(4-Acetylphenyl)-1-trimethylsilylbut-1-en-1-yl Benzo-
ate (27): Colorless oil; IR (ZnSe) 1718, 1682, 1604, 1263,
(500 MHz, CDCl3) ꢂ 1.18 (6H, t, J ¼ 7:1 Hz), 1.34 (3H, s),
1.89 (2H, tt, J ¼ 7:2, 7.2 Hz), 2.61 (2H, t, J ¼ 7:2 Hz), 2.62
(2H, t, J ¼ 7:2 Hz), 3.39 (2H, dq, J ¼ 9:2, 7.1 Hz), 3.48 (2H,
dq, J ¼ 9:2, 7.1 Hz), 7.15–7.18 (3H, m), 7.24–7.28 (2H, m);
13C NMR (125 MHz, CDCl3) ꢂ 15.3, 20.8, 24.9, 35.1, 37.1,
57.5, 102.2, 125.8, 128.3, 128.4, 141.7, 209.5; HRMS (FABþ)
Found: m=z 265.1833. Calcd for C16H25O3: (M + H)þ, 265.1804.
3,3-Dimethoxy-1-phenylbutan-2-one (23): Colorless oil; IR
1
1246, 1095, 837, 706 cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 0.14
(9H, s), 2.42 (2H, dt, J ¼ 7:1, 7.4 Hz), 2.55 (3H, s), 2.75 (2H, t,
J ¼ 7:4 Hz), 5.57 (1H, t, J ¼ 7:1 Hz), 7.22 (2H, d, J ¼ 8:3 Hz),
7.43–7.46 (2H, m), 7.55–7.59 (1H, m), 7.83 (2H, d, J ¼ 8:3
Hz), 8.00–8.03 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ ꢂ1:4,
26.5, 27.3, 35.0, 128.4, 128.4, 128.6, 129.8, 129.8, 129.9, 133.1,
135.1, 147.3, 156.0, 164.7, 197.8; Anal. Found: C, 72.02; H,
7.25%. Calcd for C22H26O3Si: C, 72.09; H, 7.15%.
(ZnSe) 1732, 1454, 1192, 1142, 1041, 889, 725, 696 cmꢂ1
;
1H NMR (500 MHz, CDCl3) ꢂ 1.34 (3H, s), 3.23 (6H, s), 3.89
(2H, s), 7.18–7.20 (2H, m), 7.21–7.25 (1H, m), 7.28–7.31 (2H,
m); 13C NMR (125 MHz, CDCl3) ꢂ 19.9, 44.5, 49.6, 102.7,
126.7, 128.3, 129.6, 133.8, 206.3; HRMS (FABþ) Found: m=z
209.1205. Calcd for C12H17O3: (M + H)þ, 209.1178.
This research was supported by the Grant-in-Aid for Scien-
tific Research (A) from Japan Society for the Promotion of Sci-
ence, and the Grant-in-Aid for The 21st Century COE program
for Frontiers in Fundamental Chemistry from the Ministry of
Education, Culture, Sports, Science and Technology.
Typical Procedure for Preparation of ꢀ-Diketone (24, 25).
To a dichloromethane–trifluoroacetic acid 10:1 solution (3 mL)
was added 2,2-dimethoxy-6-phenylhexan-3-one (22a) (77.5 mg,
0.328 mmol) at room temperature and the solution was stirred at
this temperature for 1.5 h. Then the solution was quenched with
saturated NaHCO3 solution and the organic layer was extracted
three times with dichloromethane. The combined organic extracts
were dried over magnesium sulfate. The solvent was removed un-
der reduced pressure, and the residue was purified by column
chromatography on FlorisilÒ (hexane–ethyl acetate 5:1) to afford
6-phenylhexane-2,3-dione (24) (62.4 mg, 0.328 mmol) quantita-
tively. In the case of hydrolysis of 23, only 25 was formed as a
crude material. 25 and 26 were obtained as a mixture (1:1) after
FlorisilÒ column chromatography.
References
1
For Lewis acid mediated electrophilic acylation of vinyl-
silanes, see: AlCl3; a) I. Fleming and A. Pearce, J. Chem. Soc.,
Chem. Commun., 1975, 633. b) W. E. Fristad, D. S. Dime, T. R.
Bailey, and L. A. Paquette, Tetrahedron Lett., 20, 1999 (1979).
TiCl4; c) A. Tubul and M. Santelli, Tetrahedron, 44, 3975
(1988). SnCl4; d) F. Cooke, R. Moerck, J. Schwindeman, and
P. Magnus, J. Org. Chem., 45, 1046 (1980). ZnCl2; e) T. Sasaki,
A. Nakanishi, and M. Ohno, J. Org. Chem., 47, 3219 (1982).
2
For transition metal-catalyzed Friedel–Crafts acylation of
aromatic compounds, see: a) H. Kusama and K. Narasaka, Bull.
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3 M. Yamane, K. Uera, and K. Narasaka, Chem. Lett., 33,
424 (2004).
6-Phenylhexane-2,3-dione (24):41
1776, 1712, 1496, 1454, 1354, 700 cmꢂ1
Yellow oil; IR (ZnSe)
1H NMR (500 MHz,
;
CDCl3) ꢂ 1.92 (2H, tt, J ¼ 7:3, 7.4 Hz), 2.28 (3H, s), 2.63 (2H,
t, J ¼ 7:4 Hz), 2.74 (2H, t, J ¼ 7:3 Hz), 7.14–7.19 (3H, m),
7.24–7.28 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 23.7, 24.6,
35.0, 35.0, 126.1, 128.4, 128.5, 141.2, 197.4, 199.1.
4 M. Yamane, T. Amemiya, and K. Narasaka, Chem. Lett.,
2001, 1210.
1-Phenylbutane-2,3-dione (25): Yellow oil; IR (ZnSe) 1712,
1259, 1082, 1047, 800, 727, 694 cmꢂ1
;
1H NMR (500 MHz,
5
a) A. J. Kresge and J. B. Tobin, J. Am. Chem. Soc., 112,
CDCl3) ꢂ 2.30 (3H, s), 4.03 (2H, s), 7.18–7.20 (2H, m), 7.23–
7.27 (1H, m), 7.29–7.33 (1H, m); 13C NMR (125 MHz, CDCl3)
ꢂ 24.0, 42.3, 127.2, 128.7, 129.7, 132.3, 195.8, 197.3.
2805 (1990). b) A. J. Kresge and J. B. Tobin, J. Org. Chem.,
58, 2652 (1993).
6
For oxidative addition of acid anhydride to rhodium(I)
3-Hydroxy-4-phenylbut-3-en-2-one (26):
(mixture of 25 and 26) (ZnSe) 3371, 1712, 1664, 1637, 1394,
Yellow oil; IR
species, see: a) C. G. Frost and K. J. Wadsworth, Chem. Commun.,
2001, 2316. b) K. Oguma, M. Miura, T. Satoh, and M. Nomura,
J. Organomet. Chem., 648, 297 (2002).
1352, 1244, 692 cmꢂ1; H NMR (500 MHz, CDCl3) ꢂ 2.49 (3H,
1
s), 6.44 (1H, d, J ¼ 1:1 Hz), 7.28–7.33 (2H, m), 7.37–7.40 (2H,
m), 7.81–7.83 (2H, m); 13C NMR (125 MHz, CDCl3) ꢂ 23.0,
113.8, 128.5, 128.6, 130.1, 134.0, 146.9, 195.2; HRMS (mixture
of 25 and 26) (FABþ) Found: m=z 163.0756. Calcd for C10H11O2:
(M + H)þ, 163.0759.
AlCl3-Mediated Acylation of (1-Benzoyloxyvinyl)silane
14b.20 To a dichloromethane solution (2 mL) of (E)-4-phenyl-
1-trimethylsilylbut-1-en-1-yl benzoate (14b) (64.4 mg, 0.20
7
(2002).
8
T. Hiyama and E. Shirakawa, Top. Curr. Chem., 219, 61
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K. Itami, T. Nokami, Y. Ishimura, K. Mitsudo, T. Kamei, and J.

486 Bull. Chem. Soc. Jpn., 78, No. 3 (2005)
Rhodium-Catalyzed Acylation of Vinylsilanes
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20 There is no report on Lewis acid mediated electrophilic
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(1-benzoyloxyvinyl)silane 15b with acetyl chloride in the pres-
ence of AlCl3, the desired ꢀ-benzoyloxy-ꢀ,ꢁ-unsaturated ketone
was not obtained but Friedel–Crafts acylation of phenyl group
proceeded to give 28 in 74% yield (Eq. 6).
9
For transmetalation between transition metals and alkoxy
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O
OCPh
O
OCPh
AcCl (2 mol. amt.)
AlCl3 (2 mol.amt.)
Ac
Ph(CH2)2
SiMe3
SiMe3
CH2Cl2,rt, 24 h
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27 74%
14b
ð6Þ
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