Highly Enantio- and Diastereoselective Mannich Reactions of Glycine Schiff Bases with in situ Generated N-Boc-imines Catalyzed by a Cinchona Alkaloid Thiourea

Highly enantio- and diastereoselective organocatalytic Mannich reactions of glycine Schiff bases with N-Boc-protected imines are described. Imines were generated in situ from bench-stable alpha-amido sulfones. Catalysis mediated by a cinchona alkaloid thiourea provided optically active alpha,beta-diamino acid derivatives with up to 99% ee and near-perfect diastereoselection.