Direct asymmetric Mannich-type reaction of α-isocyanoacetates with ketimines using cinchona alkaloid/copper(II) catalysts.

The enantioselective direct Mannich-type reaction of ketimines with α-isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α-isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,β-diamino acids.