Studies On The Reaction Of Hantzsch Esters And Alkylboric Acids Via Visible Light Photocatalysis

Green chemistry and sustainable development chemistry are consistent with the requirements of today’s society and have become the subject of chemical industry development.In recent years,visible light catalysis has the advantages of high efficiency good functional group tolerance and mild reaction conditions,which has aroused great interest from chemists.Its unique single-electron reaction mode has changed the traditional chemical reaction path and achieved some results that cannot be obtained by traditional chemical conversion methods.4-alkyl substituted Hantzsch esters and alkylboronic acid have the characteristics of low toxicity,simple preparation and stable chemical properties.Using the oganic chemical conversion of visible light to catalyze 4-alkyl substituted Hantzsch esters and alkylboronic acids are great significance in the fields of organic synthesis and pharmaceutical synthesis.This paper mainly studies the application of 4-alkyl substituted Hantzsch esters and alkylboronic acids in photocatalytic reaction.The dissertation is consisted of three chapters:The first chapter is a literature review.Hantzsch esters has been proved to be a kind of useful electron donor and proton source in the process of visible light catalysis,and it can also be used as a versatile alkylation reagents under photoredox conditions.At the same time,organoboron reagents are easy to prepare,and they have been widely used under visible light catalytic conditions.This chapter focuses on the application of Hantzsch esters and organoboron reagents in organic synthesis under photoredox catalysis.In the second chapter,catalyzed by Ir（ppy）₃and under N₂atmosphere,the reaction of 4-alkyl-substituted Hantzsch esters and Baylis Hillman（B-H）adducts to form trisubstituted alkenes by free radical nucleophilic reaction under visible light was studied.The reaction conditions are mild,simple to operate and without the requirement of additional additives.Various structures of 4-alkyl substituted Hantzsch esters can participate in the reaction.The reaction of B-H adducts protected by tert-butoxycarbonyl or acetyl group can be completed efficiently,which greatly expands the scope of reaction substrates.The third chapter elaborate that the defluorinated alkylation reaction ofα-trifluoromethyl olefins using alkylboronic acids as alkylating agent under the Lewis base/photoredox dual catalytic system.In this reaction system,not only the secondary carboalkyl substituted boric acids can participate in the reaction,but the primary carboalkyl substituted boric acids can also obtain the target product well.The reaction conditions are mild,the substrate range is wide and the functional group tolerance is very good,which opens up a new route for the synthesis of difluoroolefins under photocatalytic conditions.