Sulfated tungstate: A highly efficient, recyclable and ecofriendly catalyst for chemoselective N-tert butyloxycarbonylation of amines under the solvent-free conditions

Sulfated tungstate catalyzed an efficient and ecofriendly protocol has been described for the chemoselective N-tert-butyloxycarbonylation of amines under the solvent-free conditions at room temperature. The variety of functionalized aliphatic, aromatic and heteroaromatic amines efficiently undergoes the N-tert-butyloxycarbonylation under the developed protocol. The aminoalcohol, aminophenol, aminoester as well as various chiral amines underwent the chemoselective N-Boc protection under the optimized reaction condition. The rapid reaction rate, mild conditions, very good functional group tolerance, excellent yield, solvent-free, easy recovery products and excellent catalyst recyclability are the advantages of this protocol. This makes the protocol feasible, economical and environmentally benign.