Studies On 1,3-dipolar Cycloaddition Reaction Of Electron-deficient Alkynes

The synthetic strategies of the construction and cleavage of a bond is the central theme in organic synthesis.The cleavage of a bond is achieved either by weakening or by polarizing or by cleaving with suitable reagent.The driving force behind the formation of a bond is possession of opposite dipoles in nucleophilic and electrophilic substrates.Substrates bearing opposite dipoles react to the counter dipoles of other component forming desired bonds.The 1,3-dipolar cycloaddition utilizes this concept where each indivisual substrate holds opposite dipoles to form the desired molecular framework.The main constituent elements of the 1,3-dipole are usually derived from the second cycle of nitrogen,carbon,oxygen,or higher periods of sulfur and phosphorus,since they also exhibit the properties of the 1,3-dipole.It can be said that the 1,3-dipolar cycloaddition reaction is an efficient and convenient method for the construction of cyclic molecules,which has attracted the extensive attention of organic chemists in recent years.They can react with a variety of electrophilic coupling partners undergoing[2+1]?[2+3]?[2+4]?[3+3]?[3+6]annulations.In this paper,1,3-dipolar cycloaddition reactions based on two dipole intermediates of Azomethine ylide and Phosphorus ylide were explored.1.In the presence of 2-ene-4-alkynyl dicarboxylic acid diester,20 compunds were formed through the reaction of isatin with L-proline.and all of them were characterized by 'H NMR,13C NMR,IR,HRMS spectroscopies.The single crystal structures of two products were determined by X-ray diffraction method.2.Three-component reactions of triphenylphosphine,hex-2-en-4-ynedioate and arylmet-hylene indandione were studied and Twelve kinds of spiro[cyclopentane-1,2'-indene]IV3.derivative were synthesized in good yields.all products were characterized by 1H NMR,13C NMR,IR,HRMS spectroscopies.The single crystal structures of two products were determined by X-ray diffraction method.4.Three-component reactions of triphenylphosphine or tributylphosphine with dimethyl butynedione and N-methylpyrrolidone derivatives was also explored.A total of 21 compounds were obtained and were characterized by1H NMR,13C NMR,IR,HRMS spectroscopies.The single crystal structures of three products were determined by X-ray diffraction method.