Organocatalytic asymmetric Michael addition of α-branched aldehydes to vinyl ketones: synthesis of 5-ketoaldehydes possessing a stereo-controlled all-carbon quaternary stereogenic center

Abstract Synthesis of 5-ketoaldehydes possessing a highly stereo-controlled all-carbon quaternary stereogenic center was achieved by organocatalytic asymmetric Michael addition of α-branched aldehydes to vinyl ketones. A readily obtainable primary amino acid, l -phenylalanine, proved an effective catalyst for this reaction to give the 5-ketoaldehydes with high enantioselectivities (up to 95% ee).