Synthesis of β-difluorine-containing amino acids

Abstract A convenient strategy was developed to prepare several β-difluoroamino acids. As exemplified by the synthesis of 3,3-difluoro- l -homocysteine, 3,3-difluoro- l -homoserine and 3,3-difluoro- l -methionine, the reaction sequence all started from l -isoascorbic acid. This approach holds potential to be extended to make other β-difluorine-containing amino acids.