Mizoroki-Heck Type Reaction Through C-SI or C-H Bond Activation
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Date
2001-11-16
Authors
Priyadarshani, A. M. A.
Mori, A.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya, Peradeniya, Sri Lanka
Abstract
Mizoroki-Heck (MH) reaction of silanols with olefins is a feasible method to synthesize
substituted olefins by means of catalytic pailadium(II) acetate. The hydroxy group of silanol is
reported to play an important role in the reaction.
A series of reactions were carried out using silanols and silanediols and found that silanediols
have comparable reactivity towards olefins bearing electron-withdrawing groups in the
presence of stoichiometric amounts of palladium acetate. Catalytic reactions also took place
although the reactions were less effective.
The reaction of p-methoxyphenyl(ethyl) silanediol with ethyl acrylate, butyl acrylate, N,N-
dimethylacryl amide and N-tert-butylacrylamide gave the corresponding coupling products;
ethyl (2E)-3-(p-methoxy-phenyl)propenoate, butyl (2E)-3-(p-methoxyphenyl)propenoate, N,N-
dimethyl (2E)-3-(p-methoxyphenyl) propenamide and N-tert-butyl (2E)-3-(p-
methoxyphenyl)propenamide, in 39%, 45%, 60% and 40% yields, respectively. The reactions
were carried out with catalytic amounts of Pd(OAch in the presence of Cu(OAc)2 and LiOAc
in DMF at 100°C.
Carbon-carbon bond formation through catalytic activation of C-H bonds also has a
considerable interest in the pharmaceutical industry. Differently substituted benzene
derivatives were subjected to reaction with olefins in the presence the catalyst palladium (II)
acetate, and successively achieved the corresponding products in good yields. Benzene
derivatives having electron-donating groups gave higher yields when compared to those having
electron-withdrawing groups.
Further, symmetrically substituted benzene derivatives such as, 1,4-dimethoxybenzene with
ethyl acrylate, in the presence catalytic amount ofPd(OAch in DMF at 100°C, afforded ethyl
(2E)-3-(2,5-dimethoxyphenyl)propenoate in 57% yield. Unsymmetrically substituted benzene
derivatives such as anisole, 1,2-dimethoxybenzene and 1,3-dimethoxybenzene were subjected
to the coupling reaction, under similar reaction conditions and obtained mixtures of
regioisomers in 77%, 73% and 77%, respectively. The major regioisomers in each case was
identified as ethyl (2E)-3-( 4-methoxyphenyl) propenoate, ethyl (2E)-3-(2,3-
dimethoxyphenyl)propenoate and ethyl (2E)-3-(2,4-dimethoxyphenyl)propenoate,
respectively.
Description
Keywords
Mizoroki-Heck , Bond
Citation
Proceedings & abstracts of the Annual Research Sessions 2001,University of Peradeniya, Peradeniya, Sri Lanka,pp.187