Cu-catalysed transamidation of unactivated aliphatic amides

Abstract

Direct transamidation is gaining prominence as a ground-breaking technique that generates a wide variety of amides without the requirement of acid–amine coupling or other intermediate steps. However, transamidation of unactivated aliphatic amides, on the other hand, has been a long-standing issue in comparison to transamidation of activated amides. Herein, we report a transamidation approach of an unactivated aliphatic amide using a copper catalyst and chlorotrimethylsilane as an additive. In addition, we used transamidation as a tool for selective N–C(O) cleavage and O–C(O) formation to synthesise 2-substituted benzoxazoles and benzothiazoles. The reactions were carried out without using any solvents and offered wide substitution scope.