Proline-derived carboxylic acid as a bifunctional organocatalyst for highly efficient asymmetric Michael addition of aldehydes to nitroalkenes

A novel bifunctional proline amide -carboxylic acid catalyst was used for the highly stereoselective Michael reaction of various aldehydes with different nitroalkenes. This catalyst was easily prepared using commonly available anhydrides and proline linked with a diamine spacer. The asymmetric catalytic Michael reactions afforded high yields (up to 98 %), diastereoselectivities ( syn/anti ratio: up to 86:14), and enantioselectivity (up to 99 % ee ) when 5 mol% of the catalyst is used with N -methylmorpholine as a base in a dichloromethane solvent at room temperature.