Research About The Effect Of Ligand On Rh-catalyzed [3+2] Cycloaddition Of Ketimines And Alkynes

The cyclization reaction is one of the powerful synthetic methods in recent years which catalyzed by Rh^???,indene skeleton material is one of productions from it,which is a very widely used compound with high application prospects.However,the current synthesis method of indene has some limitations,moreover,the catalytic performance of Rh^???catalysts are terminate and needs to be continuously innovated.It is well known that ligands and transition metal complexes often have high enantioselectivity and regioselectivity in the reaction,but there is a little report on the effect of reaction rate.According to this situation,our main work is to study the specific effect of ligands on the reaction rate about that[Cp*Rh Cl₂]₂ catalyzed arylimine and alkyne.Through research to deepen the understanding of the reaction mechanism about[3+2]cycloaddition between imine and alkyne,it also lays the foundation for the creation of new reactions.The main work of this thesis is divided into two steps:Step 1:Study the effect of the added ligand on the reaction between imine and alkyne.The additional ligands play an important role in the change of the reaction activity of that[Cp*Rh Cl₂]₂ catalyzed ketimine and alkyne,the asymmetric carbene ligand deactivates the reaction and the norbornadiene accelerates the reaction.The kinetic constant after adding norbornadiene ligand is 1.20h^-1,which is 8 times higher than that without ligand.Norbornadiene mainly achieves the purpose of accelerating the reaction by controlling the rate of the control step,carboradation,which deepens the understanding of the reaction mechanism.It is particularly important that the method we provide for rapid synthesis of spiro-indene compounds,which is suitable for alkyl symmetrical alkyne,with a yield of 70%-95%within 5h,and also suitable for heteroatoms?furan-2-ylethynyl?trimethylsilane,the product with unique configuration was obtained with a yield of 49%.Step 2:Study the enrichment of Rh^???in the organic phase.It will inevitably cause organic rhodium waste liquid after Rh^???catalytic reaction,which can be enriched and recovered.In this paper,a simple method was used to synthesize four kinds of thiourea formaldehyde resins for studying the effect on rhodium enrichment,and the results showed that the thiourea-formaldehyde resin had a better adsorption capacity for Rh^???in methylene chloride,with an adsorption rate as high as 97.6%.