Synthesis and reaction of bromoallylsilane:A short access to beta,gamma-disustituted alpha-methylene-gamma-butyrolactone

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 1a with aldehyde gave syn-3-alkyl-2-bromo-4-hydroxyalkene (2a,2c,and 2e) 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 1a-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).