Copper-Catalyzed Asymmetric Conjugate Addition of Alkenyl- and Alkylalanes to α,β-Unsaturated Lactams

Abstract

Alkenyl and alkyl groups have been successfully introduced to six-membered α,β-unsaturated lactams via a copper-catalyzed asymmetric 1,4-addition of the corresponding alanes. Moderate to good yields and good to excellent enantioselectivities are achieved by using a combination of the very cheap copper(II) naphthenate and a readily available phosphine amine ligand. The creation of an all-carbon quaternary stereogenic center, via Michael addition to a trisubstituted conjugated lactam, is also disclosed for the first time.