Analogues of natural amino acids, in which the α-proton is replaced by an unsubstituted epoxide ring, are potential mechanism-based inhibitors for pyridoxal phosphate dependent enzymes.1 Yet, free α-oxiranyl amino acids have remained elusive until now. The synthesis of an α-(phenyl-substituted)oxiranyl amino ester has been reported. However, the accessibility and stability of the corresponding free, zwitterionic α-oxiranyl amino acid remained an open question.9