Copper-Catalyzed Asymmetric Protoboration of β-Amidoacrylonitriles and β-Amidoacrylate Esters: An Efficient Approach to Functionalized Chiral α-Amino Boronate Esters

A copper-catalyzed asymmetric protoboration of both Z-beta-amidoacrylonitriles and ethyl E-beta-amidoacrylates using bis(pinacolato)diboron has been developed for the first time. The process tolerates a vast array of substrates, delivering a series of stable functionalized chiral alpha-amino boronate esters in good yields and enantioselectivities under mild reaction conditions. The current method is also applicable for gram-scale synthesis without erosion of enantioselectivity. This work provides an attractive and complementary approach to synthesizing enantioriched chiral alpha-amino boronate esters.