Environmentally Benign N-Boc Protection under Solvent- and Catalyst-Free Conditions

Abstract

A practical and highly efficient method for the protection of amines to their corresponding N-Boc derivatives is reported. In the absence of any solvent and catalyst, the present strategy works well for a series of electron-deficient and electron-rich aromatic amines as well as some sterically hindered substrates.

Key words

N-Boc protection - environmentally benign - solvent-free - catalyst-free

References and Notes

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8

General Procedure: To Boc₂O (1 mmol) that was being magnetically stirred in oven-dried glassware at r.t. was added the amine (1 mmol). Rapid heat evolution and bubbling was then observed. The mixture was stirred until completion of the reaction. The product was purified using silica gel column chromatography eluting with hexane-EtOAc (5:1) to afford the corresponding N-Boc protected product. All of the products are known and were characterized by comparison of their spectral data with those of authentic samples.