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 C-B 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.