B（C₆F₅）₃-Catalyzed Olefin Isomerization And Transesterification

In recent years,with the vigorous development of Lewis acid-base chemistry,the strong electrophilic borane Lewis acid has attracted much attention of many chemical workers.These compounds exhibit transition metal properties in many small molecule activation and catalytic organic reactions.Lewis acids are of great significance in catalytic reactions of organic chemistry.For example,traditional Lewis acids including Al Cl₃,BF₃ and Fe Br₃ are important catalysts.Compared with traditional Lewis acid,tris（pentafluorophenyl）borane B（C₆F₅）₃ has the advantages of stable chemical properties,Lewis acidity and convenient use,and is called non-traditional Lewis acid.The catalytic reaction mechanism and results of B（C₆F₅）₃ are quite different from those of traditional Lewis acid.The application field of B（C₆F₅）₃ has been developed from the original co-catalyst for olefin polymerization to other fields including organic chemistry and polymer chemistry.Based on the above contents,this work uses B（C₆F₅）₃as a catalyst to investigate its catalytic activity for olefin isomerization and transesterification between organic esters and simple alcohols.The main work content is as follows:（1）Olefin isomerization catalyzed by B（C₆F₅）₃The catalytic performance of various electrophilic boranes on the isomerization of olefins were studied,and the possible reaction mechanism was explored.Among them,the regioselectivity and stereoselectivity are the best when the reaction is carried out in deuterated benzene with B（C₆F₅）₃ as catalyst.In addition,the reaction system is metal-free,low-cost and non-toxic,which does not require strong acids and bases.It has the advantages of good substrate scope,with up to 96%yield and up to 99:1 E/Z selectivity.（2）Transesterification catalyzed by B（C₆F₅）₃An effective method for the formation of asymmetric carbonate from vinyl acetate/dimethyl carbonate and simple alcohol catalyzed by B（C₆F₅）₃ under various conditions was studied,and the possible reaction mechanism was explored.The reaction effect is the best at 50℃for 24 h.In addition,the reaction system of vinyl acetate has the advantages of good substrate scope,and the transesterification conversion with simple alcohols can reach up to99%,and the yield is up to 95%.The reaction effect of dimethyl carbonate system with linear primary alcohol is remarkable,in which the significant selectivity is up to 97%,and the conversion and yield are up to 96%and 90%,respectively.