Synthesis of Nitrile Bearing Acyclic Quaternary Centers through Co(III)‐Catalyzed Sequential C−H Bond Addition to Dienes and N‐Cyanosuccinimide

Herein we disclose a three‐component strategy to access quaternary centers bearing nitriles by cobalt‐catalyzed C−H bond activation and sequential addition to internally substituted 1,3‐dienes and an electrophilic cyanating reagent with high regio and stereocontrol. 2‐Aryl and alkyl monosubstituted dienes provide α‐aryl and α‐alkyl α‐methyl‐substituted nitriles, respectively. An even wider variety of functionality can be installed at the quaternary carbon by using 1,2‐disubstituted dienes. The synthetic utility of the nitrile products was successfully demonstrated by various transformations, including conversions to γ‐lactones and tetrazoles. The observed connectivity in the products along with studies with deuterium labeled reactants provide insight into the mechanism. Formation of a 7‐membered cobaltacycle by C−H activation and migratory insertion of the diene is followed by β‐hydride elimination and hydride reinsertion to give a 6‐membered cobaltacycle that then reacts with the cyanating agent. A Cp*Co(III)‐catalyzed strategy to access quaternary centers bearing nitriles by C−H activation and sequential addition to internally substituted 1,3‐dienes and an electrophilic cyanating reagent is reported. 2‐Monosubstituted dienes provide α‐aryl and α‐alkyl α‐methyl nitriles, while 1,2‐disubstituted dienes introduce an even wider variety of functionality at the quaternary center. The synthetic utility of the nitrile products is disclosed.