Copper-Catalyzed Highly Enantioselective 1,4-Protoboration of Terminal 1,3-Dienes

The copper-catalyzed,highly enantioselective 1,4-protoboration of terminal 1,3-dienes with proton source and B2Pin2 has been developed.Chiral allylic boronate reagents,which are significant precursors for many well-established transformations,were prepared by this novel method with good functional group tolerance and enantioselectivity.Further studies indicated the products could be used as versatile precursors for asymmetric transformations and natural products syntheses.The mechanism of this reaction was investigated by control and reaction monitoring experiments.