A Ring-closing Reaction Of An Electron-deficient Olefin With A Brominated Active Methylene Compound

The synthesis methods for the cyclopropanes and their derivatives,the applications and some problems in the presence have been researched via literature study in this thesis.Based on the above study,a new idea of the synthesis of multisubstituted cyclopropane derivatives from electron-deficient alkenes has been proposed.And a new protocle for the synthesis of pentasubstituted cyclopropane derivatives from electron-deficient alkenes(ethyl ?-cyanocinnamate derivatives and?,?-dicyanostyrene derivatives)with 2-bromo-1,3-carbonyl compounds or bromomalononitrile were developed.Based on the experiments,the possible reaction mechanisms of the two types were proposed.The main reseach contents have been summarized as following:1.The study of K3PO4-promoted cyclopropanation of electron-deficient alkenes with 2-bromo-1,3-carbonyl compoundsBecause the carbon-carbon double bond bearing special electron-withdrawing group of cyano group,ethyl ?-cyanocinnamate derivatives la and ?,?-dicyanostyrene derivatives 4a can all smoothly reacted with 2-bromo-1,3-carbonyl compounds 2a to afford the corresponding pentasubstituted cyclopropane derivatives 3aa and 5aa in good to excellent yields(up to 99%)promoted by anhydrous K3P04 in DMF at room temperature without any protection of inert gaseous,respectively.This method has advantages that the starting materials are cheaply and accessible,and the reactions are easy for handling.Cyclopropanation that two kinds of electron-deficient olefins reacted with three kinds of 2-bromo-1,3-carbonyl compounds was deeply studied,and a new method was established in this chapter.46 products were achieved with this method and the 45 compounds are new products.The structures of all products were confirmed by their corresponding 1H NMR,13C NMR spectra and HRMS(ESI).2.The study of fast synthesis of pentasubstituted cyclopropane from ethyl?-cnayocinnamate derivatives and bromomalononitrileIn this study,ethyl a-cnayocinnamate was used as substrate,bromomalononitrile was used as reagent,the products,1-aryl-3-carbethoxy-2,2,3-tricyanocyclopropanes were smoothly obtained at 0 ? in acetonitrile(without the protection of an inert atmosphere,reacted within 1min).The products were obtained in good yields(up to 95%)in absence of catalyst.15 examples of ethyl a-cnayocinnamate were investigated in this work and 9 compounds are the new products,which indicateds that the method has wide adaptability.The structures of all products were confirmed by their 1H NMR,13C NMR spectra and HRMS(ESI).