Studies On Cyclization Reactions With Trialkyl Phosphines' Participation

Trialkyl phosphines as an important class of organic phosphine compounds,have important applications in organic synthesis.Trialkyl phosphines have strong reduction.And the reduction of phosphine plays a key role in completing the relevant chemical conversion in many classical organic reactions such as Wittig,Mitsunobu and Staudinger reaction.Trialkyl phosphines also have strong affinity because of phosphorus atom's ability of giving lone pair electrons and it's polarization.In recent years,trialkyl phosphines as nucleophilic catalysant,new organic reactio-ns based on which emerge in large numbers.Their applications in organic synthesis have already opened up new areas.These special chemical features determine its widespread use in organic synthesis.Today,researchs on organic synthesis promoted by trialkyl phosphine have become an important research direction in the field of organic chemistry,attracting interests from organic chemists.This thesis studies on cyclization reaction with trialkyl phosphines' participation.1.Three-component reactions of triphenylphosphine,dialkyl acetylenedicarboxylate and ar-ylideneindan-1,3-dione in dimethoxyethane resulted in spiro[cyclopentane-1,2'-indene]in satisf-actory yields.Furthermore,similar three-component reactions of triphenylphosphine,dialkyl but-2-ynedioate and arylidene pivaloylacetonitrile afforded densely substituted 2,3-dihydrofurans in good yields.Twenty six derivatives were obtained and were characterized by 1H NMR,13C NMR,IR,HRMS spectroscopies.The single crystal structures of four products were determined by X-ray diffraction method.2.In the presence of hexamethylphosphorous triamide,the reaction of isatin with arylidene pivaloylacetonitriles in dry methylene dichloride afforded densely substituted cyclopropanes in good yields.We have synthesized twenty seven products,and all of them were characterized by 1H NMR,13C NMR,IR,HRMS spectroscopies.The single crystal structures of two products were determined by X-ray diffraction method.3.This chapter focused on the synthesis of four target compounds.All schemes have advantages of cheap raw materials,few synthetic steps and high yields.Also,the purification process is very simple.Products were all characterized by the 1H NMR,13C NMR,GC,LC spectroscopies.