シリルメタル化を鍵過程とする触媒反応

Abstract

Transition metal-catalyzed reactions involving, or probably involving, silylmetallation as the key step are reviewed. In contrast to the extensively studied hydrometallation and carbometallation, silylmetallation, which is the addition of a transition metal-silicon bond to an unsaturated bond, has not been well studied so far for both stoichiometric and catalytic organometallic reactions. The examples cited in this review are mainly the catalytic addition reactions of organosilicon reagents (Me3Si-Y; Si-Si, Si-Sn, Si-C, Si-I, Si-Se, and Si-H) to unsaturated hydrocarbons. The initial step of these catalytic reactions is the generation of a silyl transition-metal compound, a key catalytic species, by the oxidative addition of Me3Si-Y to a transition metal complex (MLn). The resulting species, Me3Si-M-Y, undergoes silylmetallation to a carbon-carbon multiple bond to give a β-silylvinyl-or β-silylethylmetal, from which reductive elimination or coupling reaction proceeds. The catalytic reactions which, we think, are likely to involve silylmetallation are included in this review irrespective of the original authors' suggestions on the mechanism.