Study On Imcr Of Two Diffient Zwitterions Generated Simultaneously And Synthesis Of Pyrrolone Based On IMCRs

Multicomponent reactions，which are operationally simple and economical,environmentally friendly, have emerged as a powerful strategy for the synthesis ofchemically and biologically important organic frameworks. Zwitterions-basedmulticomponent reaction is an important synthetic procedure, zwitterionic speciesarised from the addition of nucleophiles ‘to the π systems are especially important.Isocyanide-based multicomponent reaction (IMCR) is very useful for thediversity-oriented synthesis of collections of compounds, which is widely used tosynthesize complicated molecules and establish compound libraries.In the first chapter, we described the history and development of themulticomponent reactions, and showed the importance of multicomponent reactionsin organic synthesis. This chapter introduced the definition of zwitterions, andsummarized isocyanide-based multicomponent reaction. We summarized themeaning and application of solvent-free reaction in all kinds of reaction type.Isocyanide and isocyanide-based multicomponent reaction were also summarized.The application, development and synthetic method of cyclopentene and pyrroleketone were introduced.In the second chapter, a novel rapid and direct isocyanide-basedfive-component reaction for the synthesis of fully substituted cyclopentenes based onaldehydes, malononitrile and isocyanoacetate has been developed. The reactionconditions were optimized with various bases, solvents at different temperatures. Thebest result was obtained using DABCO (0.5equiv) as the catalyst at40oC undersolvent-free conditions. The reaction is the first report on construction of titlecompounds by the interaction of two different zwitterions in situ simultaneously generated by the addition of DABCO and isocyanides to electrophilic systemsrespectively. The synthetic procedures have the advantages of mild reactionconditions, short reaction time, convenient handling as well as a wide substratescope, which was used to synthesize16target compounds. The synthetic method hasbeen not reported in the literatures.In the third chapter, a synthetic methodology based on IMCRs to constructpyrrolone via a one-pot reaction using CuBr (0.2equiv) as the catalyst at100oC inDMSO for4h has been developed. The reaction conditions were optimized withvarious catalyst, solvents at different temperatures. Five target compounds weresynthesized. The synthetic method was not reported in the literatures.All the new compounds synthesized were characterized by IR,1H NMR,13CNMR and HR-MS for their structures. The probable mechanism was suggested andtwo serious of the novel compounds were confirmed by X-ray diffraction analysis of5a and6a.