Chiral Brønsted acid-catalyzed enantioselective multicomponent Mannich reaction: synthesis of anti-1,3-diamines using enecarbamates as nucleophiles.
Résumé
Reaction of aldehydes 2, anilines 3, and enecarbamates 4 in dichloromethane in the presence of EtOH and a catalytic amount of chiral phosphoric acid 5 afforded the Mannich adducts which were in situ reduced to anti-1,2-disubstituted 1,3-diamines 1 in excellent diastereoselectivity and enantioselectivity.