Highly enantioselective organocatalytic conjugate addition of nitromethane to benzylidene acetones.

Six active 4-aryl-5-nitro-pentan-2-ones were synthesized enantioselectively from the corresponding 5-aryl-butenones by asymmetric Michael addition of nitromethane using an imidazolidine-type enantioselective organocatalyst. The ee ratio of the products were between 67 and 100%, determined by HPLC with Chiracel OD. Molecular and crystal structure of 3,4-methylenedioxy-phenyl-5-nitro-pentan-2-one has been studied by single crystal X-ray diffraction.