Density Functional Computations for Co(I)‐Catalyzed Intermolecular Hydroacylation of Benzaldehydes

Density functional theory (DFT) was employed to study and expound Co(I)‐catalyzed intermolecular hydroacylation of benzaldehydes. The ωB97XD/6‐31G(d,p) level (LANL2DZ(f) for I and Co) was applied to optimize all intermediates and transition states. The computational results revealed that Co(I)‐catalyzed hydroacylation went primarily through the oxidative addition, hydrogen migration, and reductive elimination, the rate‐limiting step was the reductive elimination, and the ester was dominating product. The complexation of benzaldehyde occurred prior to its oxidative addition in the active three‐coordinated cobalt‐diphosphine‐benzaldehyde intermediate. The decarbonylation would be prohibited as a result of high relative Gibbs free energies. Moreover, the role of iodide ion, the additive iPr2NEt, and the solvent toluene were studied in detail. Cobalt(I)‐catalyzed hydroacylation went primarily through the oxidative addition, hydrogen migration, and reductive elimination, the rate‐limiting step was the reductive elimination, and the ester was dominating product. The complexation of benzaldehyde occurred prior to its oxidative addition in the active three‐coordinated cobalt‐diphosphine‐benzaldehyde intermediate. The decarbonylation would be prohibited. The role of iodide ion was predicted to balance the charge of the active cobalt(I) intermediates. Both iPR2NEt and toluene interacted with HOMO, decreased the HOMO‐LUMO gap, and improved reactivity.