Mechanistic, Computational Study of Alkene-Diazene Heterofunctional Cross-Metathesis Catalyzed by Ruthenium Complexes

Density functional theory calculations were used to study the cross-metathesis reaction between diazenes and alkenes catalyzed by 17 different ruthenium complexes. Density functional theory (DFT) calculations show that such a transformation is possible for properly designed catalysts. The highest estimated reaction rates were predicted for first-generation Hoveyda-Grubbs and indenylidene catalysts. In both cases, the energy barriers of the limiting step of the entire catalytic c y c l e were predicted to be significantly lower compared to all other studied catalysts and suggest that such a process is possible under mild temperature conditions. Moreover, to better understand the sti l l unclear mechanism of azo metathesis, competing reactions that may take place in the reaction mixture were also analyzed. It was found that the association of an imine molecule instead of an olefin by the ac t i v e ruthenium complex in the propagation part of the catalytic c y c l e may compete with diazene-alkene cross-azo metathesis.

Automated summary

Density functional theory calculations were employed to investigate the potential of 17 different ruthenium catalysts in the cross-metathesis reaction between diazenes and alkenes. The results indicate that certain well-designed catalysts can facilitate this transformation. The first-generation Hoveyda-Grubbs and indenylidene catalysts are predicted to have the highest reaction rates and lower energy barriers than other catalysts, suggesting the feasibility of this process at mild temperatures. In addition, competing reactions involving the association of an imine molecule with the active ruthenium complex were also analyzed to gain a better understanding of the still unclear mechanism of azo metathesis.