Chan-Evans-Lam Amination of Boronic Acid Pinacol (BPin) Esters: Overcoming the Aryl Amine Problem.

The Chan–Evans–Lam reaction is a valuable C–N bond forming process. However, aryl boronic acid pinacol (BPin) ester reagents can be difficult coupling partners that often deliver low yields, in particular in reactions with aryl amines. Herein, we report effective reaction conditions for the Chan–Evans–Lam amination of aryl BPin with alkyl and aryl amines. A mixed MeCN/EtOH solvent system was found to enable effective C–N bond formation using aryl amines while EtOH is not required for the coupling of alkyl amines.