Regio- and Enantioselective Monoborylation of Alkenylsilanes Catalyzed by an Electron-Donating Chiral Phosphine-Copper(I) Complex

An asymmetric monoborylation of alkenylsilanes catalyzed by a copper(I) complex with the chiral bisphosphine ligand BenzP* is reported. The reaction proceeded with excellent regioselectivity and high enantioselectivity to afford the corresponding optically active organoboronate esters with a stereogenic CB bond containing a vicinal silyl group. The synthetic utility of the product is demonstrated through stepwise transformations to multifunctional optically active compounds in a stereospecific manner.