Theoretical studies of ruthenium hydride-catalyzed addition reactions of benzaldehydes to isoprenes leading to β,γ-unsaturated ketones: The role of the ligands hydride, carbonyl, chloride, and triphenylphosphine of the catalyst

Density functional theory (DFT) was used to investigate ruthenium hydride-catalyzed addition reactions of benzaldehydes to isoprenes. Calculation indicated that two π bonds of isoprene had different reactivity, and the less substituted one had better reactivity. The role of the ligands hydride, carbonyl, chloride, and triphenylphosphine of RuHCl(CO)(PPh3)3 were studied in our present work. The hydride was active, and promoted this reaction. The carbonyl or chloride was not used as a carrier of hydrogen migration reaction, so they could not change the reaction channels. The only role of them was the transformation of the electron and geometry structures of those intermediates and transition states. The triphenylphosphine decreased generally the free energies of the intermediates and transition states. The di-ruthenium complexes were not an efficient catalyst.