Copper-Catalyzed Cyanomethylation of Substituted Tetrahydroisoquinolines with Acetonitrile

A novel method for the synthesis of cyanomethylated tetrahydroisoquinolines has been developed with mild reaction conditions, good yields and a broad substrate scope. Acetonitrile, a common solvent, is for the first time used as a pronucleophile for this type of two sp3 C−H bonds cross-dehydrogenative coupling (CDC) reaction. A new oxidative system (CuCl2/TEMPO/Cs2CO3) has been established by our group, in which the mild TEMPO reagent was found to be a highly efficient oxidant.