Merging the Non-Natural Catalytic Activity of Lipase and Electrosynthesis: Asymmetric Oxidative Cross-Coupling of Secondary Amines with Ketones.

Abstract

We describe the enantioselective oxidative cross-coupling of secondary amines with ketones by combining the non-natural catalytic activity of lipase with electrosynthesis. Various 2,2-disubstituted 3-carbonyl indoles with a stereogenic quaternary carbon center were synthesized from 2-substituted indoles in yields up to 78 % with good enantio- and diastereoselectivities (up to 96 : 4 e.r. and >20 : 1 d.r.). This unprecedented protocol demonstrated that hydrolase catalysis is compatible with electrosynthesis, and the reaction can be carried out in organic solvents with a broad substrate scope and good stereoselectivity. This work provides insights into enzymatic electrosynthesis.