Copper Complex of Aminoisoborneol Schiff Base Cu2(SBAIB-d)2: An Efficient Catalyst for Direct Catalytic Asymmetric Nitroaldol (Henry) Reaction

A new bifunctional copper complex of the aminoisoborneol Schiff base Cu2(SBAIB-d)2 has been developed for the effective direct catalytic asymmetric Henry reaction. One mol% of this catalyst produces the expected Henry products in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee). The utility of the present catalyst was also extended to the Henry reaction with nitroethane and 1-nitropropane that furnished the corresponding products in moderate to high yields (up to 99%) with moderate to high enantioselectivities of syn (up to 98% ee) and anti (up to 98% ee) diastereomers. The highlights of this catalytic system are easy manipulation, air and moisture tolerance, the need for 1 mol% of an easily synthesizable catalyst and the high enantioselectivities achieved for a wide range of substrates.