Enantioselective Michael Reactions of β, β-Disubstituted Nitroalkenes: A New Approach to β<sup>2,2</sup>-Amino Acids with Hetero-Quaternary Stereocenters
An atom-economic organocatalytic asymmetric Michaelreaction of α,β,β-trisubstituted olefins has been successfully developed. The reaction exhibits excellent enantioselectivities under low loading of catalysts, and the conjugate addition products are valuable for the synthesis of novel β2,2-amino acids and β-peptides.