Synthesis of Bulky N-Acyl Heterocycles by DMAPO/Boc2O-Mediated One-Pot Direct N-Acylation of Less Nucleophilic N-Heterocycles with α-Fully Substituted Carboxylic Acids

Abstract

This report describes a general method for the one-pot direct N-acylation of N-heterocycles using our previously developed 4-(N,N-dimethylamino)pyridine N-oxide (DMAPO)/di-tert-butyl dicarbonate (Boc2O) system. This system enables one-pot N-acylation reactions to provide bulky N-acyl heterocycles starting from a wide variety of less nucleophilic N-heterocycles and sterically hindered α-fully substituted carboxylic acids in high yields. Moreover, this one-pot method does not involve pre-activation of substrates. The protocol has been successfully extended to one-pot N-acylation of 7-azaindoles.