An efficient and chemoselective Cbz-protection of amines using silica–sulfuric acid at room temperature

A simple, facile, and chemoselective N-benzyloxycarbonylation of amines using silica–sulfuric acid that proceeds under solvent-free conditions at room temperature has been achieved. These reactions are applicable to a wide variety of primary (aliphatic and cyclic) secondary amines, amino alcohols, and heterocyclic amines.