Iron‐Catalyzed anti‐Selective Carbosilylation of Internal Alkynes

Reported is the anti ‐selective carbosilylation of internal alkynes with silylborane and alkyl halides using a FeBr₂/DPPE catalyst system. The iron catalyst allows simultaneous introduction of a carbon electrophile and a silicon nucleophile to simple internal alkynes, including diaryl‐, dialkyl‐, and aryl/alkyl‐substituted alkynes, in a highly stereoselective manner. Alkyl halides are applicable as the electrophiles, thereby enabling the synthesis of a variety of tetrasubstituted alkenylsilanes. In addition, syn ‐selective carbosilylation was achieved through stereoswitching, by using a silylborane having oxygen functionality on the silyl group. This novel iron‐catalyzed carbosilylation is a useful tool for expedient synthesis of stereodefined multisubstituted olefins, a fundamental structural motif in organic chemistry.