Organic Reactions Of Arynes And Palladium-Catalyzed Decarboxylative Coupling Reaction

Arynes are highly active intermediates widely applied in organnic synthesis for the formation of the C-C bonds. This dissertation mainly focuses on palladium-catalyzed decarboxylation coupling of arynes with allylic alkynoates, carbonylation reaction of arynes, and arynes as building blocks for the construction of heteroaromatic structures.(1) Recent advances in the nucleophilic addition reactions, transition metal-catalyzed reaction and cycloaddition reactions using arynes as one reaction partners were summarized in this dissertation. The reactions of arynes were discussed on the basis of structural characteristics of arynes, ligands, catalysts, solvents effect, and so on.(2) The palladium-catalyzed decarboxylation coupling reaction of arynes with allylic alkynoates has been developed. 1-allyl-2-ethynylbenzenes were prepared in high yields under simple and mild conditions. Moreover, a possible mechanism has been proposed according to some controlled experiments.(3) The carbonylation of benzynes for selective synthesis of 1-indanones has been described.3-Substitued-l-indanones were prepared in moderate yields under 1 atm carbon monoxide atmosphere. The structures of the products were determined by X-ray analysis, and a possible mechanism was also discussed. (4) The reactions of benzynes with nitrogen ylides for the synthesis of aromatic compounds have been reported. This method provided high yields in the presence of CsF and THF. The mechanism was discussed including a 1,3-dipolar cycloaddition rearangement process.(5) We provided an effective method for synthezing anthracenes via the reaction of benzynes with 2-amino-benzophenones in good yields. The effects of solvents, catalysts, ligands and bases were investigated on the reaction to screen the optimized reacting conditions. On the basis of our results and the previously reported results, we proposed a possible mechanism.(6) Recent progress in tansition metal-catalyzed decarboxylative coupling reactions was summarized. A new route to 1,4,7-triene compounds has been subsequently developed. However, the conditions were inconsistent with the electron-withdrawing groups.(7) We reported a new method for the synthesis of pyrazolo[1,5-a]pyridine via the reaction of allenes and nitrogen ylides. In the presence of Pd(OAc)2, P(o-tol)3, NEt3 and MeCN, the reaction was carried out smoothly in moderate yields.