Synthesis of fluorinated α‐amino ketones, III. Preparation of fluorinated ketone analogues of phenylalanine, lysine, and p‐(Guanidino)phenylalanine

The synthesis of α‐amino mono‐, di‐, and trifluoromethyl and difluoromethylene ketones and their derivatives is described. A one‐pot sequence related to the Dakin‐West reaction starts from amino acids and gives the corresponding fluorinated ketone analogues in good yields. The compounds are of interest as potential inhibitors of serine proteases.