Highly Enantioselective Synthesis of α‐Amino Acid Derivatives by an NHC‐Catalyzed Intermolecular Stetter Reaction

PROTONtype: An NHC-catalyzed (NHC=N-heterocyclic carbene), highly asymmetric intermolecular Stetter reaction allows the atom-economic and efficient formation of valuable α-amino acid derivatives (see scheme); the key step is an intramolecular stereoselective protonation. For the first time, a β-unsubstituted Michael acceptor was employed successfully in this kind of reaction, most importantly, with a broad range of different aldehydes.