Synthesis Of Indoles, Pyran And Pyridine Derivatives Catalyzed By N-heterocyclic Carbenes

The discourse includes four parts..In part one, the application of N-heterocyclic carbenes (NHCs) asorganocatalyst were reviewed, including Benzoin condensation, Stetter reaction,a~3-d~3umpolung, esterification of aldehydes with alcohols and other kinds ofreactions. The base of the selection of the subject, the creative points and theresearch techniques were involved.In the second part, we introduced the NHC-catalyzed benzoin condensationunder solvent-free conditions. The new protocol has the advantages of high yield,short reaction time, simple operation and environmental friendliness.In part three, we shall disclose a green method to prepare the2,3-diarylatedindoles via NHC-triggered cascade reaction under solvent-free and metal-freeconditions.In part four, we studied the reaction of α-bromo-α,β-unsaturated aldehydesand1,3-dinucleophiles under NHC catalysis which afforded a series ofdihydropyranones and dihydropyridins. The reactions were conducted under mildconditions and were easy to run.All of the products are characterized by their IR,1H NMR. The structures ofsome products were confirmed by13C NMR and X-ray analysis further. All of thepossible reaction mechanisms were proposed.