Weak Brønsted Acid−Thiourea Co-catalysis: Enantioselective, Catalytic Protio-Pictet−Spengler Reactions

Abstract

The development of one-pot imine formation and asymmetric Pictet-Spengler reactions cocatalyzed by a chiral thiourea and benzoic acid is described. Optically active tetrahydro-beta-carbolines, ubiquitous structural motifs in biologically active natural products, are obtained in high ee directly from tryptamine and aldehyde precursors.