C–N bond metathesis: mechanistic insight into palladium-catalyzed ring-closing using aminal species

Abstract

C–N bond metathesis is a straightforward and step-economical approach for C–N bond construction. Typically, the oxidation state of the transition metal remains unchanged during C–N bond metathesis. In this report, we present computational evidence that supports a mechanism in which a new type of reversible reductive elimination/oxidative addition mode is involved in the C–N bond metathesis reaction. This reversible reductive elimination/oxidative addition-induced C–N bond metathesis pathway was found to be lower in energy compared with transimination from a Huang-complex, which is important for understanding the mechanism of Pd-catalyzed C–N bond formation reactions. Non-covalent interaction analysis was conducted to elucidate the details of the diene 1,4-migratory insertion step process and to investigate the origin of stereoselectivity for this type of reaction. We anticipate that this novel C–N bond metathesis mode may extend to other cross-coupling processes and may provide a theoretical guide for further experimental investigations.