Study On The [3+2] 1,3-Dipolar Cycloaddition Of Aryne To Nitrones And Synthesis Of Series Of EDOT Monomers Derivatives

鈽匟eterocycle compounds are of great importance due to their fundamental roles as building blocks for natural products, bioactive substances and chiral pharmaceuticals. In recent years, great progress has been made in the synthesis of hetercycle compounds developing with the study of the synthesis. The [3+2] 1,3-dipolar cycloaddition reaction and the intermolecular nucleophilic substitution cyclization reaction are two of the most important methods for the synthesis of hetercycle compounds.鈽匢n this thesis, the [3+2] 1,3-dipolar cycloaddition reaction of aryne to nitrones was studied. We have synthesized a series of very easily accessible nitrones and aryne precursor. Influence of catalyst, the solvent type, the dosage of material, and reaction temperature on the yield of the product was investigated. It is found that cesium fluoride has a high catalytic activity in the reaction as compared with the other catalysts. When the base was cesium fluoride, the solvent was CH₃CN, molar ratio of 17 to 18 was 1:1．3, the reaction temperature was 50鈩? the yield of product was 90%. Under optimal reaction conditions, 2,3-disubstituted benzo[d]isoxazolidines first were prepared by [3+2] 1,3-dipolar cycloaddition reaction between aryne precursor o-trimethylsilylphenyl triflate and a series of nitrones under mild conditions with yield higher than 90%, and the products were characterized by H-NMR銆?C-NMR銆丠RMS.鈽匴e have firstly described the direct double intermolecular nucleophilic substitution cyclization reactions of functional group activated thiophene (2-nitro-3,4-dibromothiophene) with a variety of diols catalyzed by sodium hydride. The optimal experiment conditions were found: the solvent was THF, molar ratio of 2 to 3 was 1:1．2, the reaction temperature was 50鈩? The method merits attention because of the good to high yields usually observed (50锝?9%), the use of simple and readily available starting materials, and the reaction is a useful and efficient method for the synthesis of a new series of 2-position nitryl substitute 3,4-ethylenedioxythiophene(EDOT) monomers and derivatives. The samples were characterized by ¹H-NMR銆亊(13) C-NMR and the elemental analysis.