Synthesis of beta-difluorine-containing amino acids

A convenient strategy was developed to prepare several beta-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 beta-difluorine-containing amino acids.