摘要:
(Z)-beta-Bromoallylsilanes (1a-c) were prepared by a stereoselective Ni-catalyzed cross-coupling reaction of 1,1-dibromo-4-phenylbutene (4) with silylmethylmagnesium halide. Sakurai-Hosomi reaction of la with aldehyde gave syn-3-alkyl-2-bromo-4-hydroxyalkene (2a, 2c, and 2c) and that with acetal gave syn-4-alkoxy-3-alkyl-2-bromoalkene (2b and 2d) stereoselectively. The products with formyl function reacted with a Ni-carbonyl complex to give beta,gamma-disubstituted (alpha-methylene-gamma-butyrolactones (3) in good yields. Pd-catalyzed cross-coupling reaction of la-c or 4 with silylmethylmagnesium halide gave 1, 1-bis(silylmethyl)-1-alkenes (1d-i), which reacted with dimethyl acetal to generate more functionalized allylsilane (6).