Chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions via in situ generation of NOCl

A combination of inorganic chloride salts [e.g. WCl6, AlCl 3 and ZnCl 2 ] and sodium nitrite in the presence of wet SiO 2 were used as an effective nitrosating agent for the nitrosation of secondary amines to their corresponding nitroso derivatives under mild and heterogeneous conditions in moderate to excellent yields.