The Investigation Of Nickel-Catalyzed Heck Cyclization/Cross-coupling Reaction

Organic-chemical synthesis,as the cornerstone of organic chemistry,is an important tool for synthetic chemists to create substances.How to use simple,efficient,safe and green method to synthesize target compounds has always been the pursuit of organic synthetic chemists.The ideal organic synthesis is to convert 100%of raw materials into target compounds without any waste.Chemists have been pursuing this goal all the way.Domino reaction,frequently also described as cascade or tandem reaction,is an important green synthesis mode,which is the formation of multiple chemical bonds through one operation for a group of reactions with similar conditions.As one of the most common domino reactions,transition metal-catalyzed olefin difunctional reactions have attracted much attention from chemists.Among them,palladium-catalyzed domino reactions,which initiated by Heck cyclization,have been well developed.However,palladium is toxic and expensive,which restricts its application in industrial production.Our research tries to develop some new strategy to solve this problem by using cheaper nickel as catalyst.At the beginning of the paper,the development status and reaction mechanism of palladium or nickel-catalyzed domino reactions via Heck cyclization were summarized firstly through literature review.Then,an idea of the nickel-catalyzed Heck cyclization/coupling reaction model was proposed to replace the palladium-catalyzed process.Specially,the difunctionalization of alkene by the reduction cross-coupling reaction,which was not involved in the field of palladium catalysis was conceived.The main achievements of this paper in this field are as follows:1.A series of 3,3-disubstituted oxindole derivatives containing quaternary all-carbon centers were synthesized by nickel-catalyzed domino Heck cyclization/Suzuki coupling reaction.In addition,cheap aryl esters could also be used as electrophiles,which undergo catalytic Csp~2-O bond cleavage.The reaction,which beared wide substrate scope and cheaper and less toxic catalyst,had better practicability.2.Through Heck cyclization/reduction cross-coupling reaction mode,we had synthesized a series of 3-allylindolene compounds containing quaternary all-carbon centers by using cheap nickel bromide as catalyst and manganese powder as reductant.The reaction conditions were simple and mild,which tolerated various functional groups.Many natural alkaloids could be synthesized by simple derivatization of product.This method has very important synthetic value.As an important green synthesis method,oxidative coupling reaction has been a hot research field in organic chemistry during last ten years.The tert-butanol and different kinds of mercaptans for construction of?-OH thioethers were reported for the first time by oxidative cross-coupling.In this reaction,NIS was used to regulate the activity of free radicals,so that the two active radicals could be selected for cross-coupling.