2,4,5-Trifluoro-L-_-homophenylalanine hydrochloride is used as a reagent in the synthesis of valuable _-amylalkyl-_-amino acid enantiomers. It is also an impurity of Sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor for the treatment of diabetes mellitus type 2.