ABSTRACT
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.
ABSTRACT
Chiral C2-symmetric 3,3'-bis((R,R)-2-naphthylethylaminomethyl)-(R)-binaphthol (AMB4) functions as an efficient organocatalyst for the asymmetric epoxidation of various alkylidenemalononitriles. The spiro-epoxyoxindole products obtained from isatilidenemalononitriles were easily transformed to the corresponding chiral dihydroquinoxalinyl spirooxindoles.