Elucidating the Mechanism and Selectivities of Cobalt‐Catalyzed Transformation of <i>O</i>‐Acyl Oxime

ABSTRACT In this work, the mechanistic investigation on the cobalt‐catalyzed CH functionalization of O ‐acyl oxime and verification of the origin of selectivities are employed using the density functional theory (DFT) method. Based on the calculations, the most energetically favorable pathway contains four steps: coordination of Co(III) species to the O ‐acyl oxime, para ‐selective CH activation to give a five‐membered cobaltacycle, [2,1]‐alkyne insertion, and redox‐cyclization to give the final product and regenerate the Co(III) species. IRC calculations clearly indicate that the redox‐cyclization process occurs in a concerted but highly asynchronous manner. The structural analysis reveals that the para ‐CH activation occurs preferentially mainly due to the less steric hindrance. FMO analysis and energetic span model are used to disclose the origin of regioselectivity and chemoselectivity, respectively.