Enantio- and diastereoselective double Mannich reaction of malononitrile with -Boc imines using quinine-derived bifunctional organoiodine catalyst

A chiral quinine-derived organic base catalyst with halogen bond donor functionality was used to catalyze the asymmetric double Mannich reaction of malononitrile with N -Boc and N -Cbz imines to afford 1,3-diamines in excellent yields with high enantio- and diastereoselectivities. With 2.2 equiv. of a single imine electrophile, symmetrical 1,3-diamines were obtained, whereas, with two different imine partners, unsymmetrically substituted 1,3-diamine was obtained. The monohydration of the double Mannich product was also achieved. A chiral organic base catalyst with halogen bond donor functionality was used to promote the asymmetric double Mannich reaction to afford 1,3-diamines in excellent yields with high enantio- and diastereoselectivities.