Synthesis of Non-Natural Amino Acids Based on the Ruthenium-Catalysed Oxidation of a Phenyl Group to Carboxylic Acid

Abstract

An efficient method for the synthesis of enantiopure β-, γ-, and δ-amino acids with proteinogenic side chains, starting from natural α-amino acids, was developed. The method is based on the ruthenium-catalyzed oxidation of a phenyl group to a carboxylic acid. β-Amino acids may be prepared starting from Boc-phenylalaninol. The route described for the synthesis of γ- and δ-amino acids permits the insertion of any chain length between the amino and carboxy functionalities as a result of the original choice of the starting ylide chain length.