NHC-AuCl Catalyzed Carboheterofunctionalization Of Alkenes And Mechanism Study Of1,5-Vinyl Shift

This paper is divided into two parts, the first part introduces NHC-AuCl catalyzedcarboheterofunctionalization of alkenes, and the second part introduces the mechanisms studyof1,5-vinyl shift in the reaction between vinylphenyl furan and alkyne.The first part: NHC gold catalysts have been widely used in organic synthesis. Our groupis strongly interested in the reactions catalyzed by NHC-Au, and strive to explore the design,synthesis and catalytic applications of such ligands. This part describes NHC-AuCl catalyzedintermolecular carboheterofunctionalization reactions between alkenyl amine and arylboronicacid. Under the optimal conditions, various substituted alkenyl amine reacted well with aseries of arylboronic acids to form the corresponding coupling products. moreover, it issuitable for the internal alkenes. Then a wide variety of alkene substrates such as N-allylamides, alcohols, carboxylic acids, and ureas was tested, both of them ultimately succeeded inobtaining the tetrahydrofuran, lactones, and imidazolidin-2-one products. Finally, a possiblemechanism of this reaction was proposed, that is the alkyl gold complex reacted witharylboronic acid via a five-centered transition-state simultaneously with the B-F bondinteraction. Finally, a bimolecular reductive elimination took place to afford the product.The second part: As a common reaction type of most intermediates,[1,j] shift resultingin stable molecules in organic reactions has been reported widely. However, there’re stillfewer reports about1,5-vinyl shift process in literatures so far. To further investigate thistransformation,2-(2-vinyl)-phenyl furan was initially used to react with DMAD in toluene,followed by the related researches under the different temperatures, solvents and catalysts.Experimental results showed that the products were totally different both in the presence andabsence of a ZnCl2catalyst, or in the water simply. After optimizing the reaction conditions, arange of furan substrates were expanded and gave good results. To explore the reactionmechanism, numerous proving experiments were carried out and a certain transformationrelationships of the products became visible. Based on the results and theoretical analysis, apossible mechanism about a key initial step1,5-vinyl shift was proposed for these reactions.