Cu-Catalysed Coupling of Aliphatic Amines with Alkylboronic Esters

We report a Cu-catalysed oxidative coupling of aliphatic amines with alkylboronic esters to give high value alkyl amines, products found widely in applications from medicinal chemistry to materials science. This operationally simple reaction, which can be performed on gram scale, runs under mild conditions and exhibits excellent functional group tolerance. The terminal oxidant of the reaction is O2 from the air, avoiding the need for additional chemical oxidants. Investigation into the reaction mechanism suggests the intermediacy of an alkyl radical, generated from the boronic ester upon activation through an amino radical transfer process. To demonstrate its utility and potential for late-stage functionalization, we showcase the method as the final step in the total synthesis of a TRPV 1 antagonist.