Theoretical study on copper-catalyzed reaction of hydrosilane, alkyne and carbon dioxide: A hydrocarboxylation or a hydrosilylation process ?

The hydrocarboxylation and hydrosilylation processes proposed in the copper-catalyzed reaction among carbon dioxide, diphenylacetylene and HSi(OEt)3 were comparatively studied with the aid of density functional theory calculations. Our study is to explore why the reaction preferred a hydrocarboxylation rather than a hydrosilylation process. It was found that the σ bond metathesis between Cu–C and H–Si involved in the hydrosilylation process had a significantly high reaction barrier in the presence of CO2 (47.4 kcal/mol). Instead, CO2 insertion and the subsequent σ bond metathesis between Cu–O and H–Si involved in the hydrocarboxylation process were confirmed kinetically feasible, consistent with the experimental facts.