ABSTRACTIn this work, the mechanistic investigation on the cobalt‐catalyzed CH 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 CH 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‐CH 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.
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