Preparation and addition--elimination reactions of benzyl alpha,beta,beta-trifluoroacrylate. A new stereoselective approach to (Z)-beta-substituted alpha,beta-difluoroacrylates.
Benzyl alpha,beta,beta-trifluoroacrylate (1) was prepared in good yield via the reductive Br-F elimination of benzyl 2-bromo-2,3,3,3-tetrafluoropropanoate or the palladium-catalyzed cross-coupling reaction of 1,2,2-trifluorovinylstannane with benzyl chloroformate. On treating 1 with various Grignard reagents or dialkylzinc reagents in the presence of copper(I) salt, the corresponding beta-substituted alpha,beta-difluoroacrylates were obtained in high yields with high Z-selectivity. Additionally, trialkylaluminum reagents were also found to be good nucleophiles, the corresponding addition-elimination products being afforded in good yields but with low stereoselectivity.
Yamada
Shigeyuki
S
Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan.
Noma
Mayumi
M
Hondo
Kazunori
K
Konno
Tsutomu
T
Ishihara
Takashi
T