1,1,1,3,3,3-Hexafluoroisopropanol: A Recyclable Organocatalyst for N-Boc Protection of Amines

Abstract

A simple and efficient protocol for the chemoselective mono-N-Boc protection of various structurally diverse amines with di-tert-butyl dicarbonate using 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) as solvent and catalyst is described. The catalyst can be readily separated from the reaction products and recovered for direct reuse. No competitive side reactions such as formation of isocyanate, urea, and N,N-di-Boc were observed. α-Amino alcohols afforded the N-Boc derivatives without oxazolidinone formation.

Key words

amines - Boc anhydride - chemoselectivity - HFIP - organocatalyst - hydrogen bonding

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