title: Organo[2-(hydroxymethyl)phenyl]dimethylsilanes as mild and reproducible agents for rhodium-catalyzed 1,4-addition reactions.
abstract: Stable and reusable tetraorganosilicon reagents, alkenyl-, aryl-, and silyl[2-(hydroxymethyl)phenyl]dimethylsilanes, undergo 1,4-addition reactions to alpha,beta-unsaturated carbonyl acceptors under mild rhodium-catalysis. The reaction tolerates a diverse range of functional groups and is applicable to gram-scale synthesis. Use of a chiral diene ligand allows the achievement of the corresponding enantioselective transformations using the tetraorganosilicon reagents, providing the silicon-based approach to optically active ketones and substituted piperidones that serve as synthetic intermediates of pharmaceuticals. A rhodium alkoxide species is suggested to be responsible for a transmetalation step on the basis of the observed kinetic resolution of a racemic chiral phenylsilane in the enantioselective 1,4-addition reaction under the rhodium-chiral diene catalysis.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan. nakao@npc05.kuic.kyoto-u.ac.jp
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nakao
authors.forename: Jinshui
authors.initials: J
authors.lastname: Chen
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Imanaka
authors.forename: Tamejiro
authors.initials: T
authors.lastname: Hiyama
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Ichikawa
authors.forename: Wei-Liang
authors.initials: WL
authors.lastname: Duan
authors.forename: Ryo
authors.initials: R
authors.lastname: Shintani
authors.forename: Tamio
authors.initials: T
authors.lastname: Hayashi