Pyrrolidine-Camphor Derivative as an Organocatalyst for Asymmetic Michael Additions of α,α-Disubstituted Aldehydes to β-Nitroalkenes: Construction of Quaternary Carbon-Bearing Aldehydes under Solvent-Free Conditions

A novel pyrrolidine-camphor organocatalyst 3 was designed, synthesized and proven to be an efficient catalyst for the asymmetric Michael reaction. Treatment of alpha,alpha-disubstituted aldehydes with beta-nitroalkenes in the presence of 20 mol% organocatalyst 3 and 20 mol% benzoic acid under solvent-free conditions provided the desired Michael product possessing an all-carbon quaternary center with high chemical yields (up to 99% yield) and high levels of enantioselectivities (up to 95% ee).