A New Combined Source of CN from N,N-Dimethylformamide and Ammonia in the Palladium-Catalyzed Cyanation of Aryl C-H Bonds

An unprecedented protocol for cyanation at arene C-H bonds has been developed by employing N,N-dimethylformamide and ammonia as a combined source for the cyano CN unit. Isotopic incorporation experiments revealed that the carbon and nitrogen of the CN originate from the N,N-dimethyl moiety of DMF and ammonia, respectively. The present cyanation reaction shows an excellent degree of regioselectivity, producing only monosubstituted nitriles at the less hindered C-H position, and it allows for the preparation of doubly labeled nitrile compounds for the first time.