Amino Imidate Catalyzed Asymmetric Michael Reactions of Ketones and Nitroalkenes

The efficiency of an amino imidate organocatalyst was evaluated in the Michael reaction of ketones with nitroalkenes. tert-Butyl­ l-proline imidate was found to be a syn-selective catalyst, generating products with moderate to good enantioselectivities of up to 84% ee. The best substrates were found to be cyclic ketones and β-nitrostyrenes. The catalytic efficiency and enantioselectivity were enhanced by the addition of 10 mol% of benzoic acid.