Mechanistic insights into catalytic linear cross-dimerization between conjugated dienes and styrenes by a ruthenium(0) complex

•The mechanistic studies for linear cross-dimerization between 2,3-dimethylbuta-1,3-diene and styrene by a Ru(0) complex.•Kinetic studies which support the oxidative coupling mechanism.•DFT calculations consistent with the kinetic studies.

The mechanistic studies for linear cross-dimerization between 2,3-dimethylbuta-1,3-diene and styrene by a Ru(0) complex, Ru(η6-naphthalene)(η4-1,5-COD) (1), are performed both by kinetic and computational studies. This reaction is basically zero-order to both of the diene and styrene concentrations and first-order to the catalyst concentration. The Hammett plot using p-substituted styrenes gives a linear relationship with a positive slope (ρ = +0.482). The deuterium isotope experiment clearly shows the present reaction being a formal 1,4-addition of a C–H bond in styrene to cisoid-1,3-diene. These kinetic studies show the reaction proceeding via oxidative coupling mechanism that is also supported by the DFT calculations.

Graphical abstractThe mechanistic studies for linear cross-dimerization between 2,3-dimethylbuta-1,3-diene and styrene by a Ru(0) complex are performed both by kinetic and computational studies, and these results support the oxidative coupling mechanism.Figure optionsDownload full-size imageDownload as PowerPoint slide