Palladium complex catalyzed acylation of allylic esters with acylsilanes

Article abstract of DOI:10.1021/ja010674p

Acylation of allylic esters (2) with acylsilanes (1) in the presence of a catalytic amount (5 mol %) of a palladium complex is reported. The reaction proceeds selectively to afford β, γ-unsaturated ketones (3) in high yields. [Pd(η³-C₆

Full text of DOI:10.1021/ja010674p

J. Am. Chem. Soc. 2001, 123, 10489-10493
10489
Palladium Complex Catalyzed Acylation of Allylic Esters with
Acylsilanes
Yasushi Obora,‡ Yasuhiro Ogawa,† Yuji Imai,† Takashi Kawamura,† and Yasushi Tsuji*,‡
Contribution from the Catalysis Research Center and DiVision of Chemistry, Graduate School of Science,
Hokkaido UniVersity, Sapporo 060-0811, Japan, and Department of Chemistry, Faculty of Engineering,
Gifu UniVersity, Gifu 501-1893, Japan
ReceiVed March 13, 2001
Abstract: Acylation of allylic esters (2) with acylsilanes (1) in the presence of a catalytic amount (5 mol %)
of a palladium complex is reported. The reaction proceeds selectively to afford â,γ-unsaturated ketones (3) in
high yields. [Pd(η3-C6H5CHdCHCH2)(CF3COO)]2 (4a) showed the best catalytic activity. After the reaction,
formation of CF3COOSiMe3 (5a) was confirmed by 29Si NMR measurement of the resulting reaction mixture,
indicating the trimethylsilyl moiety effectively traps the CF3COO leaving group from 2. The leaving group of
the allylic esters affects the reaction considerably: allylic trifluoroacetate gave the best result, while the
corresponding acetates and trichloroacetates did not afford any acylation products at all. Stoichiometric reaction
of 4a with 1 gave acylation product 3 with a formation of 5a and Pd(0), whereas no acylation reaction took
place with the corresponding acetate complex [Pd(η3-C6H5CHdCHCH2)(CH3COO)]2 (4b). A DFT calculation
suggests that interaction of high-lying HOMO of 1 and low-lying LUMO of η3-allylpalladium trifluoroacetate
intermediate 4 would be indispensable in the catalytic cycle.
Introduction
â,γ-Unsaturated carbonyl compounds are versatile starting
materials in a variety of synthetic reactions.4 If acyl functionality
can be introduced in the palladium-catalyzed nucleophilic
substitution of allylic esters, the reaction will be a potent
synthetic method. However, generation of nucleophilic acyl
species5 is usually difficult, since carbonyl functionality is found
to be a good electrophile. Consequently, to realize the acylation
reaction of allylic esters, carbonylative three-component cou-
pling reactions with allylic benzoates, carbon monoxide, and
organozinc compound were reported.6,7 More recently, acylzir-
conocene chloride8a and chromium carbene complexes8b were
employed in palladium-catalyzed acylation of allylic acetates
or allylic bromide, respectively, but both of these reactions
afforded acylation products only as a mixture of regioisomers.
We have developed palladium-catalyzed silylation9 and
cyanation10 reactions of allylic esters using disilanes and silyl
The palladium(0)-catalyzed nucleophilic substitution of allylic
esters1 via η3-allylpalladium intermediate is one of the most
important homogeneous catalyses, since it has numerous ap-
plicabilities in synthetic organic chemistry.2 So far, a number
of nucleophiles such as stabilized carbanions,3a,b enolates,3c,d
organotin compounds,3e-g and amines3h,i have been successfully
employed in the reaction. However, functionality that can be
directly introduced to the allylic system is still limited.
Therefore, unexploited and capable functionalities should be
explored to make the catalytic reaction more proficient.
‡ Hokkaido University.
† Gifu University.
(1) (a) Tsuji, J. Palladium Reagents and Catalysts; Wiley: Chichester,
UK, 1995. (b) Harrington, P. J. In ComprehensiVe Organometallic Chemistry
II; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford,
UK, 1995; Vol. 12, pp 797-904. (c) Trost, B. M. Acc. Chem. Res. 1996,
29, 355. Trost, B. M. Acc. Chem. Res. 1980, 13, 385. (d) Trost, B. M.; Van
Vranken, D. L. Chem. ReV. 1996, 96, 395. (e) Tsuji, J.; Minami, I. Acc.
Chem. Res. 1987, 20, 140. (f) Tsuji, J. Pure Appl. Chem. 1980, 54, 197.
Tsuji, J. Pure Appl. Chem. 1980, 58, 869. (g) Tsuji, J. Tetrahedron 1986,
42, 4361. (h) Matsuhashi, H.; Asai, S.; Hirabayashi, K.; Hatanaka, Y.; Mori,
A.; Hiyama, T. Bull. Chem. Soc. Jpn. 1997, 70, 1943.
(2) (a) Godlesky, S. A. In ComprehensiVe Organic Synthesis; Trost, B.
M., Fleming, I., Eds.; Pergamon: Oxford, UK, 1991; Vol. 4, pp 585-661.
(b) McQuillin, F. J.; Parker, D. G.; Stephenson, G. R. Transition Metal
Organometallics for Organic Synthesis; Cambridge: New York, 1991;
Chapter 6. (c) Harrington, P. J. Transition Metals in Total Synthesis;
Wiley: New York, 1990; Chapter 3.
(3) (a) Tsuji, J.; Takahashi, H.; Morikawa, M. Tetrahedron Lett. 1965,
21, 4387. (b) Trost, B. M.; Verhoeven, T. R. In ComprehensiVe Organo-
metallic Chemistry; Wilkinson, G., Stone, F. G. A., Abel, E. W., Eds.;
Pergamon: Oxford, UK, 1982; Vol. 8, Chapter 57, p 799. (c) Negishi, E.;
Matsushita, H.; Chatterjee, S.; John, R. A. J. Org. Chem. 1982, 47, 3188.
(d) Trost, B. M.; Self, C. R. J. Org. Chem. 1984, 49, 468. (e) Trost, B. M.;
Keinan, E. Tetrahedron Lett. 1980, 21, 2595. (f) Godschalx, J. P.; Stille, J.
K. Tetrahedron Lett. 1980, 21, 2599. (g) Gollaszewski, A.; Schwartz, J.
Organometallics 1985, 4, 417. (h) Trost, B. M.; Genet, J. P. J. Am. Chem.
Soc. 1976, 98, 8516. (i) Trost, B. M.; Keinan, E. J. Org. Chem. 1979, 44,
3451.
(4) (a) Van Der Weerdt, A. J. A.; Cerfontain, H. Tetrahedron 1981, 37,
2121. (b) Ito, N.; Etoh, T.; Hagiwara, H.; Kato, M. Synthesis 1997, 153.
(c) Borecka, B.; Gudmundsdottir, A. D.; Olovsson, G.; Ramamurthy, V.;
Scheffer, J. R.; Trotter, J. J. Am. Chem. Soc. 1994, 116, 10322. (d) Banerjee,
A. K.; Acevedo, J. C.; Gonzalez, R.; Rojas, A. Tetrahedron 1991, 47, 2081.
(5) (a) Lever, O. W., Jr. Tetrahedron 1976, 32, 1943 and references
therein. (b) Seyferth, D.; Hui, R. C.; Wang, W.-L.; Archer, C. J. Org. Chem.
1993, 58, 5843. (c) Hanzawa, Y.; Narita, K.; Taguchi, T. Tetrahedron Lett.
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(6) Tamaru, Y.; Yasui, K.; Takanabe, H.; Tanaka, S.; Fugami, K. Angew.
Chem., Int. Ed. Engl. 1992, 31, 645.
(7) For similar acylation of allylic chlorides by carbonylative three-
component coupling reaction with allylic halides, carbon monoxide, and
organotin, see: (a) Sheffy, F. K.; Godschalx, J. P.; Stille, J. K. J. Am. Chem.
Soc. 1984, 106, 4833. (b) Merrifield, J. H.; Godschalx, J. P.; Stille, J. K.
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(8) (a) Hanzawa, Y.; Tabuchi, N.; Taguchi, T. Tetrahedron Lett. 1998,
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S.; Funato, M. J. Org. Chem. 1993, 58, 3607.
(10) (a) Tsuji, Y.; Kusui, T.; Kojima, T.; Sugiura, Y.; Yamada, N.;
Tanaka, S.; Ebihara, M.; Kawamura, T. Organometallics 1998, 17, 4835.
(b) Tsuji, Y.; Yamada, N.; Tanaka, S. J. Org. Chem. 1993, 58, 16.
10.1021/ja010674p CCC: $20.00 © 2001 American Chemical Society
Published on Web 10/09/2001

10490 J. Am. Chem. Soc., Vol. 123, No. 43, 2001
Obora et al.
Scheme 1
ties: the yield of 3a was 53% with Pd(OCOCF3)2, 27% with
Pd(DBA)2, 12% with Pd(OCOCH3)2, and 0% with Pd(OSO2-
CF3)2. Palladium complexes with phosphine ligands such as
PdMe2(PMePh2)2, PdCl2(PPh3)2, Pd(DBA)2 combined with P(n-
Bu)3 (P/Pd ) 3), and Pd(DBA)2 combined with P(OCH2)3CC2H5
(P/Pd ) 3) totally suppressed the catalytic activity. Addition
of CsF or n-Bu4NF to the catalyst system lowered the yield to
<5%.15 Other metal complexes such as Pt(DBA)2 and (C5Me5)-
RuCl(COD) did not show any catalytic activity at all. As for
the solvent, THF gave the best result. Toluene and dioxane could
be used similarly. However, strongly coordinated solvents such
as CH3CN and DMF lowered the yields considerably.
The acylation reaction of 2a with acylsilanes such as
nonanoyl- (1b), butyryl- (1c), 4-methylvaleryl- (1d), and 3-me-
thylbutyrylsilane (1e) gave the corresponding (E)-â,γ-unsatur-
ated ketones regio- and stereoselectively in good yields (entries
2-5). Various allylic trifluoroacetates (2b-e) can be employed
in the reaction affording the corresponding acylation products
regioselectively (entries 6-10).16 However, the reaction of
benzoyltrimethylsilane (C6H5(CdO)SiMe3) with 2a was slug-
gish and not stereoselective to afford the corresponding ketone
in 26% yield with stereoisomers (E:Z ) 88:12).
cyanide as silylation and cyanation reagents, respectively
(Scheme 1, i and ii). In these reactions, the silyl and the cyano
functionalities were transferred from the silyl moieties of the
reagents with concomitant formation of the Si-O bonds.
In this paper, we design the novel acylation reaction using
acylsilanes (1)11 as acylation reagents (Scheme 1, iii). A wide
variety of acylsilanes are prepared readily, and these stable and
easily accessible substrates are utilized in various organic
syntheses.12 Nevertheless, so far, there is only one example for
the transition metal catalyzed reaction with 1 as a substrate,
i.e., benzocyclobutanone synthesis from o-(R-phenylthio)alkyl-
benzoyltrimethylsilanes.13 Herein, we report that 1 functions as
a good acylation reagent for allylic trifluoroacetates in the
presence of a palladium catalyst via Si-C σ-bond cleavage of
1 with formation of the Si-O bond (eq 1).
Noteworthy is that leaving groups of the allylic esters affect
the reaction considerably (eq 2). The trifluoroacetate (2a) gave
the highest yield. The corresponding pentafluoropropionate (2f)
and dichlorofluoroacetate (2g) gave 3a in 67% and 54% yields,
respectively. The carbonate (2h) only afforded 3a in 7% yield.
Further, the corresponding trichloroacetate (2i) and acetate (2j)
did not afford any acylation product at all.17 Among the acetates,
esters of stronger acid seem to have higher reactivity.
Results and Discussion
Results are listed in Table 1. When the reaction of 3-phen-
ylpropionyltrimethylsilane (1a) with cinnamyl trifluoroacetate
(2a) was carried out in the presence of a catalytic amount of
[Pd(η3-C6H5CHdCHCH2)(CF3COO)]2 (4a) (5 mol %), the
acylation product (3a) was obtained regio- and stereoselectively
in high yield (entry 1). The product is only â,γ-unsaturated
ketone, and no R,â-unsaturated isomers were detected. 29Si
NMR measurement of the resulting reaction mixture after the
reaction confirmed a comparable formation of CF3COOSiMe3
(5a: 33.6 ppm, lit.14 33.1 ppm), indicating the Me3Si moiety
of 1a effectively trapped the CF3COO leaving group from 2a.
The reaction of 1a with 2a was carried out under various
conditions. As a catalyst precursor, 4a gave the best result (entry
1). Other palladium complexes showed lower catalytic activi-
In the previous silylation9 and cyanation10 reaction of allylic
esters, the silyl moiety effectively trapped the oxygen-containing
leaving groups by forming the Si-O bond (Scheme 1). Strong
oxophilicity of the silicon atom may be an important driving
force for these successful reactions. In the present acylation
reaction, a comparable formation of CF3COOSiMe3 (5a) was
confirmed after the reaction by 29Si NMR (vide supra),
suggesting the strong oxophilicity of the silicon atom might
operate similarly. For the marked effect of the trifluoroacetate
moiety (2a) as compared with acetate (2j) in eq 2, the stronger
Si-O bond of 5a than that of CH3COOSiMe3 (5b), which
should have been obtained in the reaction with 2j, might be
responsible. Thus, to estimate bond dissociation energies of the
Si-O bonds of 5a and 5b, ab initio molecular orbital calculation
with the MP4/6-31+G(2d,p)//B3LYP/6-31G(d) method19 was
(11) (a) Page, P. C. B.; Klair, S. S.; Rosenthal, S. Chem. Soc. ReV. 1990,
19, 147. (b) Qi, H.; Curran, D. P. In ComprehensiVe Organic Functional
Group Transformations; Katrinsky, A. R., Meth-Cohn, O., Rees, C. W.,
Moody, C. J., Eds.; Pergamon: Oxford, UK, 1995; pp 409-431. (c) Brook,
M. A. Silicon in Organic, Organometallic, and Polymer Chemistry; John
Wiley & Sons: New York, 2000. (d) Cirillo, P. F.; Panek, J. S. Org. Prep.
Proc. Int. 1992, 24, 553.
(12) (a) Colvin, E. W. Silicon Reagents in Organic Synthesis; Aca-
demic: London, UK, 1988; Chapter 12. (b) Ricci, A.; Degl’Inniocenti, A.
Synthesis 1989, 647. (c) Cheng, S.-y.; Jiaang, W.-f.; Cherng, C.-d.; Tang,
K.-h.; Huang, C.-h.; Tsai, Y.-m. J. Org. Chem. 1997, 62, 9089. (d) Bonini,
B. F.; Comes-Franchini, M.; Fochi, M.; Mazzanti, G.; Ricci, A. J.
Organomet. Chem. 1998, 567, 181. (e) Sakurai, H.; Yamane, M.; Iwata,
M.; Saito, N.; Narasaka, K. Chem. Lett. 1996, 841.
(15) (a) Degl’Inniocenti, A.; Ricci, A.; Mordini, A.; Reginato, G.; Colotta,
V. Gazz. Chim. Ital. 1987, 117, 645. (b) Ricci, A.; Degl’Innocenti, A.;
Chimichi, S.; Fiorenza, M.; Rossini, G.; Bestmann, H. J. J. Org. Chem.,
1985, 50, 130.
(16) Allylic trifluoroacetates with substituents at the R-position such as
2-cyclohexenyl trifluoroacetate did not give any acylation products at all.
(17) In eq 2, only allylic esters containing a fluorine atom (2a, 2f, and
2g) afford the acylation product. It is well-known that a fluoride anion
strongly interacts with a silicon atom of silanes.18 However, there will be
no direct interaction between the fluorine atom of 2 and the silicon atom
of 1 in eq 2, since 29Si NMR measurement of a mixture of 1a and 2a in the
absence of a palladium catalyst at 70 °C in toluene-d8 showed the 29Si
resonance of 1a at 9.73 ppm did not change.
(13) Kang, J.; Choi, Y. R.; Kim, B. J.; Jeong, J. U.; Lee, S.; Lee, J. H.;
Pyun, C. Tetrahedron Lett. 1990, 31, 2713.
(14) Bassingdale, A. R.; Posnan, T. B. J. Organomet. Chem. 1979, 175,
273.

Acylation of Allylic Esters with Acylsilanes
J. Am. Chem. Soc., Vol. 123, No. 43, 2001 10491
Table 1. Palladium-Complex-Catalyzed Acylation of Allylic Trifluoroacetatesa
a Conditions: 1 (0.50 mmol), 2 (1.0 mmol), 4a (0.025 mmol), and THF (0.5 mL) under reflux for 16 h. b Isolated yields. Numbers in parentheses
show GLC yield determined by the internal standard method. c E:Z ) 71:29. d E:Z ) 63:37. e E:Z ) 68:32.
carried out for the heterolytic (eq 3) and the homolytic cleavage
(eq 4). However, in both cases, lower (by ca. 20 kcal/mol) Si-O
Consequently, simple comparison of the Si-O bond dissociation
energies between 5a and 5b could not explain the distinct effect
of the trifluoroacetate moiety of 2a in eq 2.
The most plausible catalytic cycle for the present acylation
is shown in Scheme 2. The catalytic cycle will be initiated by
the oxidative addition of allylic ester (2) to Pd(0) to give an
η3-allylpalladium intermediate (4) (step a). This step has been
well-studied.20 Subsequently 4 reacts with acylsilane (1) to
afford 5 and the acylation product (3), possibly via 6. There is,
however, no precedent for the reactions of η3-allylpalladium
species with 1.21 Therefore, a model reaction for step b was
carried out. As model compounds of 4 for the reaction of 2a
and 2j, 4a and (η3-cinnamyl)palladium acetate dimer (4b) were
prepared, respectively. Then, stoichiometric reaction of 4a and
4b with 1a was carried out at 70 °C as the model for step b (eq
5). As a result, 4a provided 3a with a concomitant formation
bond dissociation energy was calculated for 5a than for 5b.
(18) (a) Damrauer, R.; O’Connell, B.; Danahey, S. E.; Simon, R.
Organometallics 1989, 8, 1167. (b) Damrauer, R.; Danahey, S. E.
Organometallics 1986, 5, 1490.
(19) The Gaussian 98 package: Frisch, M. J.; Trucks, G. W.; Schlegel,
H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Zakrzewski, V. G.;
Montgomery, J. A.; Stratmann, R. E.; Burant, J. C.; Dapprich, S.; Millam,
J. M.; Daniels, A. D.; Kudin, K. N.; Strain, M. C.; Farkas, O.; Tomasi, J.;
Barone, V.; Cossi, M.; Cammi, R.; Mennucci, B.; Pomelli, C.; Adamo, C.;
Clifford, S.; Ochterski, J.; Petersson, G. A.; Ayala, P. Y.; Cui, Q.;
Morokuma, K.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.; Foresman,
J. B.; Cioslowski, J.; Ortiz, J. V.; Stefanov, B. B.; Liu, G.; Liashenko, A.;
Piskorz, P.; Komaromi, I.; Gompartz, R.; Martin, R. L.; Fox, D. J.; Keith,
T.; Al-Laham, M. A.; Peng, C. Y.; Nanayakkara, A.; Gonzalez, C.;
Challacombe, M.; Gill, P. M. W.; Johnson, B. G.; Chen, W.; Wong, M.
W.; Andres, J. L.; Head-Gordon, M.; Replogle, E. S.; Pople, J. A. Gaussian
98; Gaussian: Pittsburgh, PA, 1988.
of CF3COOSiMe3 (5a) and Pd (0),22 while no acylation product

10492 J. Am. Chem. Soc., Vol. 123, No. 43, 2001
Obora et al.
Scheme 2
in eq 5 and the catalytic cycle (step b, Scheme 2). To realize
such interaction with the high-lying HOMO of 1, the lower lying
LUMO of 4 containing the CF3COO moiety would be indis-
pensable.
Experimental Section
Materials. The reagents and the solvents were dried and purified
before use by the usual procedures.26 The following catalyst precursors
and complexes were prepared by the published methods: 4a,27 4b,28
Pd(OCOCF3)2,29 Pd(OCOCH3)2,30 Pd(OSO2CF3)2,30 Pd(DBA)2,31 PdCl2-
(PMePh2)2,32 and Pd(PPh3)4.33 Acylsilanes 1 were prepared according
to published methods.12a-d Allylic trifluoroacetates were obtained with
the corresponding alcohols.
Analytical and Computational Procedures. All manipulations were
performed under argon atmosphere in conventional Schlenk-type
glassware on a dual-manifold Schlenk line. NMR spectra were recorded
on a Bruker ARX-400 (1H, 400 MHz; 13C, 100 MHz; 29Si, 79.3 MHz).
The mass spectra were measured on a Shimadzu QP-5050A (EI) and
a JEOL JMS-700TZ (HRMS, EI). The GC analysis was made on a
Shimadzu GC-8APF equipped with an integrator (C-R6A) with a
column (3 mm i.d. × 3 m) packed with Silicon OV-17 (2% on Uniport
HP, 60/80 mesh) or Apiezon Grease L (5% on Uniport HP, 60/80 mesh).
IR spectra were measured on a Shimadzu FT-IR-8300. Elemental
analysis was preformed at the Center for Instrumental Analysis of
Hokkaido University. Molecular orbital calculations were performed
with the Gaussian 98 package19 on an HP Exemplar V2500 at the
Computing Center of Hokkaido University.
was obtained at all by the reaction of 4b with 1a. This
observation is very consistent with the catalytic reaction (eq
2), in which 2a gave the acylated product, while 2j did not.
One of the most characteristic feature of acylsilanes (1) is
their much lower oxidation potentials than those of the corre-
sponding ketones and aldehydes23a,b which induce unique
spectroscopic behavior.23c,d This is due to higher HOMO24a
levels caused by strong mixing of the Si-CO σ-orbital and the
localized oxygen lone pair.24b,c Thus, electrochemical oxidation
of acylsilanes occurs easily with a facile cleavage of the Si-
CO σ-bonds.23a,b As shown in eq 5, the reactivity of 4a and 4b
is quite different. To gain further insight into this different
reactivity, DFT calculation was performed on [Pd(η3-C3H5)(CF3-
COO)]2 (4c) and [Pd(η3-C3H5)(CH3COO)]2 (4d), models for 4a
and 4b, with the B3LYP/LANL2DZ method.19 LUMOs of 4c
and 4d look very similar, consisting of antibonding interaction
between nonbonding π (nπ) of the η3-C3H5 and the palladium
d orbital (8, see Supporting Information). However, LUMO
Acylation Procedure. A typical procedure is described for the
synthesis of 3a. A mixture of 1a (103 mg, 0.5 mmol), 2a (230 mg, 1.0
mmol), 4a (14 mg, 0.025 mmol), and THF (0.5 mL) and a magnetic
stirring bar were placed under an argon flow in a 20 mL round-bottomed
flask with stirring for 16 h under reflux. After the reaction, the whole
mixture was passed through a short Florisil column (8 mm i.d. × 50
mm) to afford a clear yellow solution. GLC analysis (OV-17) with
eicosane as an internal standard showed 3a was formed in 78% yield.
The product (3a) was isolated by medium-pressure column chroma-
tography (silica gel with hexane/EtOAc ) 98/2) followed by Kugelrohr
distillation in 60% yield (pot temperature 180 °C/1 mmHg).
1
3a: white solid; mp 56-57 °C; H NMR (CDCl3) δ 2.83 (t, J ) 7
Hz, 2H), 2.95 (t, J ) 7 Hz, 2H), 3.31 (d, J ) 7 Hz, 2H), 6.31 (dt, J )
16 Hz, 7 Hz, 1H), 6.47 (d, J ) 16 Hz, 1H), 7.21-7.39 (m, 10H); 13C
NMR (CDCl3) δ 29.8 (CH2), 44.0 (CH2), 47.2 (CH2), 121.9 (CH), 126.2
(CH), 126.3 (CH), 127.6 (CH), 128.4 (CH), 128.57 (CH), 128.60 (CH),
133.9 (CH), 136.9 (C), 141.0 (C), 207.7 (C); IR (neat, cm-1) 1713
(νCdO); MS (relative intensity) m/z 250 (M+, 6), 134 (3), 117 (19), 105
(100), 91 (95); HRMS calcd for C18H18O 250.1358, found 250.1360.
Anal. Calcd for C18H18O: C, 86.36; H, 7.25. Found: C, 86.07; H, 7.31.
3b:34 colorless oil; 148 °C(pot)/0.1 mmHg; 1H NMR (CDCl3) δ 0.88
(t, J ) 7 Hz, 3H), 1.20-1.36 (m, 10H), 1.54-1.63 (m, 2H), 2.48 (t, J
) 7 Hz, 2H), 3.31 (d, J ) 7 Hz, 2H), 6.32 (dt, J ) 16, 7 Hz, 1H), 6.47
energy of 4c (-2.537 eV) is much lower than that of 4d (-1.628
eV). It might be conceivable that HOMO-LUMO interaction25
(one-electron transfer or concerted) between 1 and 4 is requisite
(25) (a) Albright, T. A.; Burdett, J. K.; Whangbo, M. H. Orbital
Interactions in Chemistry; Wiley: New York, 1985. (b) Fleming, I. Frontier
Orbitals and Organic Chemical Reactions; Wiley: New York, 1976. (c)
Rauk, A. Orbital Interaction Theory of Organic Chemistry, 2nd ed.;
Wiley: New York, 2001.
(20) (a) Trost, B. M.; Verhoeven, T. R. J. Am. Chem. Soc. 1980, 102,
4730. (b) Hayashi, T.; Hagihara, T.; Konishi, M.; Kumada, M. J. Am. Chem.
Soc. 1983, 105, 7767 and references therein.
(21) For reactions of η3-allylpaladium chloride with acyl transition metal
complexes, see: Hegedus, L. S.; Tamura, R. Organometallics 1982, 1, 1188.
(22) The reaction would proceed via (η3-allyl)(acyl)palladium species
6. However, we could not isolate or even detect 6, which may be unstable
under the reaction conditions to afford 3 and Pd(0) black or mirror.
(23) (a)Yoshida, J.-i.; Itoh, M.; Matsunaga, S.-i.; Isoe, S. J. Org. Chem.
1992, 57, 4877. (b) Yoshida, J.-i.; Matsunaga, S.-i.; Isoe, S. Tetrahedron
Lett. 1989, 30, 5293. (c) Brook, A. G.; Quigley, M. A.; Peddle, G. J. D.;
Schwartz, N. V.; Warner, C. M. J. Am. Chem. Soc. 1960, 82, 102. (d)
Harnish, D. F.; West, R. Inorg. Chem. 1963, 2, 1082.
(24) (a) Since there has been no explicit comparison of HOMO energy
between acylsilanes (1) and the corresponding ketones, it was calculated
for Me(CdO)SiMe3 (1f) and Me(CdO)CMe3 (7): HOMO energy, -9.747
(1f) and -10.580 eV (7) by HF/6-31G(2d, p); -5.940 (1f) and -6.463 eV
(7) by B3LYP/6-31G(d). (b) Bock, H.; Seidl, H. J. Am. Chem. Soc. 1969,
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60, 1365.

Acylation of Allylic Esters with Acylsilanes
J. Am. Chem. Soc., Vol. 123, No. 43, 2001 10493
1
(d, J ) 16 Hz, 1H), 7.20-7.43 (m, 5H); 13C NMR (CDCl3) δ 14.1
(CH3), 22.7 (CH2), 23.7 (CH2), 29.16 (CH2), 29.22 (CH2), 29.4 (CH2),
31.8 (CH2), 42.5 (CH2), 47.0 (CH2), 122.2 (CH), 126.3 (CH), 127.5
3h (as a mixture of E and Z): H NMR (CDCl3) δ 1.57-1.77 (m,
9H), 1.99-2.12 (m, 4H), 2.65-2.77 (m, 2H), 2.87-2.98 (m, 2H), 3.09
(d, J ) 7 Hz, 2H), 5.07 (t, J ) 6 Hz, 1H), 5.29 (t, J ) 7 Hz, 1H),
7.14-7.22 (m, 3H), 7.24-7.31 (m, 2H); 13C NMR (E isomer) δ 16.4
(CH3), 17.7 (CH3), 25.7 (CH3), 26.5 (CH2), 29.8 (CH2), 39.6 (CH2),
42.9 (CH2), 43.8 (CH2), 115.6 (CH), 123.8 (CH), 126.4 (CH), 128.3
(CH), 128.5 (CH), 131.7 (C), 139.5 (C), 141.1 (C), 208.7 (C); 13C NMR
(Z isomer) δ 17.7 (CH3), 23.5 (CH3), 25.7 (CH3), 26.3 (CH2), 29.8
(CH2), 32.8 (CH2), 42.6 (CH2), 43.7 (CH2), 116.3 (CH), 123.9 (CH),
126.4 (CH), 128.3 (CH), 128.5 (CH), 132.0 (C), 139.4 (C), 141.1 (C),
208.7 (C); IR (neat, cm-1) 1715 (νCdO); GC/MS (E isomer), (relative
intensity) m/z 270 (M+, 1), 227 (6), 201 (5), 133 (16), 122 (17), 107
(12), 105 (100), 91 (76), 79 (10), 77 (12), 69 (63), 67 (13); GC/MS (Z
isomer) (relative intensity) m/z 270 (M+, 1), 227 (4), 201 (14), 133
(14), 122 (29), 107 (17), 105 (100), 95 (13), 91 (76), 81 (19), 79 (15),
77 (16), 71 (13), 69 (62), 65 (11), 57 (25), 55 (23); GC/HRMS (E
isomer) calcd for C19H26O 270.1984, found 270.1978; GC/HRMS (Z
isomer) calcd for C19H26O 270.1984, found 270.1979.
(CH), 128.6 (CH), 133.6 (CH), 136.9 (C), 209.0 (C); IR (neat, cm-1
)
1717 (νCdO); MS (relative intensity) m/z 258 (M+, 5), 141 (63), 123
(5), 117 (26), 116 (8), 115 (26), 91 (14), 81 (15), 71 (75), 67 (10), 57
(100), 55 (23).
1
3c:35 colorless oil; 154 °C (pot) /0.5 mmHg; H NMR (CDCl3) δ
0.92 (t, J ) 7 Hz, 3H), 1.63 (sex, J ) 7 Hz, 2H), 2.47(t, J ) 7 Hz,
2H), 3.31 (d, J ) 7 Hz, 2H), 6.33 (dt, J ) 16, 7 Hz, 1H), 6.47 (d, J )
16 Hz, 1H) 7.21-7.41 (m, 5H); 13C NMR (CDCl3) 13.8 (CH3), 17.2
(CH2), 44.4 (CH2), 47.0 (CH2), 122.2 (CH), 126.3 (CH), 127.5 (CH),
128.7 (CH), 133.6 (CH), 136.9 (C), 209.0 (C); IR (neat, cm-1) 1715
(νCdO); MS (relative intensity) m/z 188 (5), 117 (20), 115 (22), 91 (11),
71 (100).
3d: colorless oil; 178 °C (pot)/0.5 mmHg; 1H NMR (CDCl3) δ 0.88
(d, J ) 7 Hz, 6H), 1.44-1.62 (m, 3H), 2.48 (t, J ) 7 Hz, 2H), 3.32 (d,
J ) 7 Hz, 2H), 6.32 (dt, J ) 16, 7 Hz, 1H), 6.48 (d, J ) 16 Hz, 1H),
7.28-7.41 (m, 5H); 13C NMR (CDCl3) δ 22.4 (CH3), 27.7 (CH), 32.5
(CH2), 40.6 (CH2), 46.9 (CH2), 122.3 (CH), 126.3 (CH), 127.5 (CH),
128.6 (CH), 133.6 (CH), 137.0 (C), 209.2 (C); IR (neat, cm-1) 1715
(νCdO); MS (relative intensity) m/z 216 (M+, 6), 145 (3), 117 (31), 115
(29), 99 (73), 91 (19), 81 (100), 71 (38), 57 (11), 55 (16). HRMS calcd
for C15H20O 216.1514, found 216.1508.
3e: colorless oil; 165 °C (pot)/0.5 mmHg; 1H NMR (CDCl3) δ 0.94
(d, J ) 7 Hz, 6H), 2.15-2.25 (m, 1H), 2.39 (d, J ) 7 Hz, 2H), 3.32
(d, J ) 7 Hz, 2H), 6.32 (dt, J ) 16, 7 Hz, 1H), 6.48 (d, J ) 16 Hz,
1H); 13C NMR (CDCl3) δ 23.0 (CH3), 25.0 (CH), 47.8 (CH2), 51.9
(CH2), 122.5 (CH), 126.7 (CH), 127.9 (CH), 129.0 (CH), 134.1 (CH),
137.3 (C), 209.4 (C); IR (neat, cm-1) 1713 (νCdO); MS (relative
intensity) m/z 202 (M+, 4), 117 (15), 115 (16), 91 (9), 85 (62), 57
(100); HRMS calcd for C14H18O 202.1358, found 202.1352.
3f: colorless oil; 180 °C (pot)/1 mmHg; 1H NMR (CDCl3) δ 1.43-
1.62 (m, 6H), 2.06-2.16 (m, 4H), 2.74 (t, J ) 7 Hz, 2H), 2.89 (t, J )
7 Hz, 2H), 3.09 (d, J ) 7 Hz, 2H), 5.21 (t, J ) 7 Hz, 1H), 7.15-7.22
(m, 3H), 7.25-7.31 (m, 2H); 13C NMR (CDCl3) δ 26.7 (CH2), 27.6
(CH2), 28.4 (CH2), 29.0 (CH2), 29.8 (CH2), 37.1 (CH2), 42.1 (CH2),
43.6 (CH2), 112.4 (CH), 126.1 (CH), 128.3 (CH), 128.5 (CH), 141.2
(C), 143.9 (C), 208.7 (C); IR (neat, cm-1) 1715 (νCdO); MS (relative
intensity) m/z 242 (M+, 9), 133 (14), 109 (11), 105 (100), 91 (63), 79
(24), 77 (19), 67 (59), 65 (15), 55 (23); HRMS calcd for C17H22O
242.1671, found 242.1662.
1
3i (as a mixture of E and Z): H NMR δ 1.01 (t, J ) 7 Hz, 3H),
1.22-1.41 (m, 12H), 1.60-1.67 (m, 6H), 1.76 (s, 3H), 2.10-2.26 (m.
6H), 2.95-3.02 (m, 2H), 5.23-5.31 (m, 1H), 5.52-5.61 (m, 1H); 13
C
NMR (E isomer) δ 14.5 (CH3), 16.6 (CH3), 17.9 (CH3), 23.2 (CH2),
24.3 (CH2), 26.0 (CH3), 27.1 (CH2), 29.8 (CH2), 29.8 (CH2), 30.0 (CH2),
32.4 (CH2), 40.2 (CH2), 42.2 (CH2), 42.9 (CH2), 117.3 (CH), 124.8
(CH), 131.6 (C), 138.6 (C), 207.2 (C); 13C NMR (Z isomer) δ 14.5
(CH3), 16.6 (CH3), 23.2 (CH2), 23.7 (CH3), 24.3 (CH2), 26.0 (CH3),
26.9 (CH2), 29.78 (CH2), 29.80 (CH2), 30.0 (CH2), 32.4 (CH2), 32.6
(CH2), 42.4 (CH2), 42.6 (CH2), 118.1 (CH), 124.7 (CH), 131.9 (C),
138.6 (C), 207.2 (C); IR (neat, cm-1) 1717 (νCdO); GC/MS (E isomer)
278 (M+, 0.2), 23 (1), 209 (3), 141 (16), 123 (8), 122 (17), 107 (14),
81 (22), 71 (60), 68 (20), 67 (29), 57 (100); GC/MS (Z isomer) 278
(M+, 0.3), 235 (1), 209 (17), 141 (23), 137 (5), 123 (12), 122 (34),
107 (34), 95 (10), 81 (35), 71 (7), 69 (74), 68 (15), 67 (27), 57 (100),
55 (29); GC/HRMS (E isomer) calcd for C19H34O 278.2610, found
278.2615; GC/HRMS (Z isomer) calcd for C19H34O 278.2610, found
278.2615.
Reaction of [Pd(η3-PhCHdCHCH2)(CF3COO)]2 (4a) with 1a (eq
5). In a 5 mm i.d. NMR tube, 4a (30 mg, 0.04 mmol) and mesitylene
(20 µL, an internal standard for 1H NMR spectroscopy) were dissolved
in degassed THF-d8 (0.3 mL). Then, 3-phenylpropionyltrimethylsilane
(1a) (9 mg, 0.04 mmol) was added into the solution at room
temperature. The reaction was carried out at 70 °C for 16 h.
Acknowledgment. The authors are grateful to Professor K.
Hori of Yamaguchi University for useful discussion. This work
was supported by Grant-in-Aid for Scientific Research on
Priority Area “Molecular Physical Chemistry” (No. 11166202)
from the Ministry of Education, Science and Culture, Japan.
Financial support from the Asahi Glass Foundation is also
gratefully acknowledged.
3g: 1H NMR (CDCl3) δ 1.38-1.52 (m, 1H), 1.74 (s, 3H), 1.87-
2.02 (m, 3H), 2.06-2.22 (m, 3H), 2.78 (t, J ) 7 Hz, 2H), 2.90 (t, J )
7 Hz, 2H), 3.02 (s, 2H), 4.72 (s, 1H), 4.74 (s, 1H), 5.51-5.57 (m,
1H), 7.17-7.23 (m, 3H), 7.26-7.32 (m, 2H); 13C NMR (CDCl3) δ
21.2 (CH3), 28.0 (CH2), 29.5 (CH2), 30.2 (CH2), 31.2 (CH2), 41.0 (CH2),
43.6 (CH2), 52.7 (CH), 109.5 (CH2), 126.3 (CH), 128.7 (CH), 128.9
(CH), 129.3 (CH), 131.7 (C), 141.6 (C), 150.1 (C), 209.0 (C); IR (neat,
cm-1) 1715 (νCdO); MS (relative intensity) m/z 268 (M+, 3), 135 (9),
133 (19), 120 (12), 105 (100), 93 (10), 92 (9), 91 (96), 79 (18), 77
(17), 65 (12), 55 (9); HRMS calcd for C19H24O 268.1827, found
268.1826.
Supporting Information Available: Optimized structures,
their Cartesian coordinates, and LUMOs for 4c and 4d (PDF).
This material is available free of charge via the Internet at
http://pubs.acs.org.
(35) Shono, T.; Nishiguchi, I.; Ohmizu, H. Chem. Lett. 1977, 1321.
JA010674P