Synthesis And Characterization Of Ruthenium Carbene Complexes Chelated With A Bidentate Ligand For Z-Selective Olefin Metathesis Reaction

Olefin metathesis refers to the reaction in which carbon-carbon double bonds of olefin molecules are cut off and recombined to form new olefin molecules under metal catalysts.Under the catalysis of modern highly efficient ruthenium carbene catalysts,the metathesis reaction of olefin can make the carbon-carbon double bonds which are not easily broken to be coupled,exchanged,or adjusted each other under mild conditions.These reactions often release ethylene as the only by-product,which has a good atomic economy.Olefin metathesis has become an important tool for the synthesis of olefin,or the construction of other compounds through olefin,which has attracted wide attention from both academic and industrial field.How to produce Z-olefins through metal carbene catalyst is one of the most challenging problems in research filed of olefin metathesis.In this paper,based on developed Z-selective Ru-based catalyst chelated with benzene-1,2-dithiolate,we synthesized two Z-selective Ru-based olefin metathesis complexes through the change of steric hindrance and electronic effect of ligands,then we studied the properties of new Z-selective catalysts.1.A ruthenium carbene catalyst chelated with 1,2-dicarbadodecaborane-1,2-dithiolate ligand was synthesized for olefin metathesis.The new ruthenium complex is very stable in the air or solvent.When Lewis acid is added to the catalyst system,the complex can catalyze cross metathesis(CM)reactions of terminal alkenes with(Z)-but-2-ene-1,4-diol to give a good activity.And this new Ru-based catalyst has good functional group adaptability.2.A ruthenium carbene catalyst chelated with 3-cyclobutene-1,2-dione-3,4-dithiolate ligand was synthesized for olefin metathesis,whose molecular structure was determined by X-ray single crystal diffraction.This ruthenium carbene complex could catalyze the cross metathesis reaction of different terminal olefins with(Z)-but-2-ene-1,4-diol with excellent Z-selectivity(94:6~98:2).The self coupling reaction of terminal olefins and cross metathesis reactions of different terminal olefins under this catalyst were also studied.This catalyst,with simple structure,good catalytic performance and high stereoselectivity,will have good application prospect.