Enantiopure α-Trifluoromethylated Aziridine-2-carboxylic Acid (α-TfmAzy): Synthesis and Peptide Coupling

A straightforward synthesis of enantiopure alpha-trifluoromethyl aziridine-2-carboxylic acid (alpha-TfmAzy) is reported from a trifluoropyruvate derived enantiopure oxazolidine. A key Strecker-type synthetic step and a late cyanide basic hydrolysis gave the target compounds in six steps and 41% yield. A final peptide coupling was performed to demonstrate the usefulness of this highly constrained fluorinated unnatural amino acid.