The Study Of [3+2] Oxidative Cycloaddition Of Phenol Derivatives And Olefins By Heterogeneous Photocatalysis

The products of[3+2]oxidative cycloaddition reaction of phenol derivatives and olefins--dihydrobenzofurans are widely distributed in natural products,which have many biological activities such as anti-cancer,anti-inflammatory,analgesic and so on,so this reaction has attracted intense attention of many chemists.At present,the[3+2]oxidative cycloaddition reaction of phenol derivatives and olefins for preparation of dihydrobenzofurans is mainly realized by homogeneous catalysis or direct oxidation,and the heterogenous photocatalytic method is few.Considering the heterogeneous photocatalysis has many advantages such as green,economic and convenient for industrialization,the heterogenous photocatalytic[3+2]oxidative cycloaddition of phenol derivatives and olefins was studied for providing a green and economic strategy to construct dihydrobenzofurans in this thesis.This thesis includes four chapters,the first chapter mainly summarizes the progress of heterogeneous photocatalyst and the research progress of[3+2]oxidative cycloaddition of phenol derivatives and olefins.In the second chapter,the[3+2]oxidative cycloaddition of phenol derivatives and olefins was studied by Ag₃PO₄ photocatalysis.Ag₃PO₄photocatalyst was firstly prepared and characterized,then Ag₃PO₄ photocatalytic reaction was studied by conditions screening,substrate scope,mechanism exploring and repeated experiment of catalyst.The research results show that under the reaction conditions of Xe lamp?500W?as light source,Ag₃PO₄ as photocatalyst,1,1,1,3,3,3-Hexafluoro-2-propanol?HFIP?as solvent and t-BuOOH as oxidant,the[3+2]oxidative cycloaddition of phenol derivatives and olefins was realized and 20 kinds of dihydrobenzofurans was obtained.In the third chapter,the[3+2]oxidative cycloaddition of phenol derivatives and olefins was studied by BiVO₄ photocatalysis.Firstly,Bi VO₄ photocatalyst was prepared and characterized,then the reaction conditions,substrate scope and recycle of catalyst was studied.The research results demonstrate that the optimum reaction condition for this reaction is BiVO₄ as heterogeneous catalyst,hydrogen peroxide?H₂O₂ 30%?as oxidant,HFIP as solvent,and 21 kinds of dihydrobenzofurans was synthesized by this method.The fourth chapter mainly introduces the experiment operation and spectral data of this thesis.In conclusion,the heterogeneous photocatalytic[3+2]oxidative cycloaddition of phenol derivatives and olefins was studied in this thesis.The results present that both of heterogeneous photocatalysis by Ag₃PO₄ and heterogeneous catalysis by BiVO₄ are efficient for realizing the[3+2]oxidative cycloaddition of phenol derivatives and olefins and two green strategies for construction of dihydrobenzofurans are developed.This work made some significant contribution to the application of heterogeneous photocatalysis in organic synthesis.