We describe a mild and efficient method for the chemoselective N-benzyloxycarbonylation of amines by treatment of amines and aminoesters with benzyloxycarbonyl chloride (Cbz-Cl) in the presence of TBAB under solvent-free conditions in excellent yields. The method is general for the preparation of a wide variety of N-Cbz derivatives of aliphatic, aromatic amines, and aminoesters.
