Synthesis of Nitrile Bearing Acyclic Quaternary Centers via 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.