Styrylisoxazoles as Cinnamate Equivalents

Significance

The authors use 4-nitro-5-styrylisoxazoles as acceptors in enantioselective Michael additions catalyzed by cinchonidine catalyst 1. Not only nitromethane but also secondary and tertiary nitroalkanes could be used. The reaction provides the corresponding Michael adducts in good to high yields and high enantioselectivities. The 4-nitro-5-styrylisoxazoles are stable solids and can be easily prepared in large quantities (10-100 mmol) from commercially available 3,5-dimethyl-4-nitroisoxazole and aromatic or heteroaromatic aldehydes.