An Asymmetric Michael Addition of α,α-Disubstituted Aldehydes to Maleimides Leading to a One-Pot Enantioselective Synthesis of Lactones Catalyzed by Amino Acids

A cheap and fast construction of both enantiomers of substituted succinimides is reported. alpha- or beta-amino acids, such as beta-phenylalanine and alpha-tert-butyl aspartate, were found to be efficient organocatalysts for the reaction between alpha,alpha-disubstituted aldehydes and maleimides. Products containing contiguous quaternary-tertiary stereogenic centers are obtained in high to quantitative yields and excellent selectivities utilizing low catalyst loadings (0.5-3.5%). Finally, a one-pot efficient asymmetric synthesis of lactones is described.