Cyclization Research Of 2-trifluoromethyl-1-alkenes With Bisnucleophilic Reagents

Nitrogen or oxygen containing five-membered and six-membered cyclic skeletons as important building blockes in organic synthesis, are widely found in many natural product sand drugs. In recent decades, organic fluorine chemistry has made considerable progress and development, a large number of studies have found various of fluorine-containing heterocyclic compounds possess more special physiological activity compared to their nonfluorinated counterparts, which have drawn considerable attention. Creating heterocyclic skeletons containing fluorine atom, has opened up new areas of organic synthesis, provided the possibility of obtaining some new bioactive molecules.In the first part of this dissertation,2-trifluoromethyl-l-alkenes which are synthesized according to the related literatures, react with bisnucleophilic 1,3-dicarbonyl compounds. We developed a straightforward and efficient approach to structurally diverse and synthetically useful ring-fluorinated 4H-pyrans via a simple base-mediated cascade reaction. Further, by the transformation of ring fluorinated 4H-pyran, we synthesized many types of highly substituted enol lactone, a-Pyrones substances, which are important building blocks in organic synthesis.In the second part of this dissertation, we examined the reactions of 2-trifluoromethyl-l-alkenes with diethyl 2-(4-methylphenyl sulfonamido) malonates which were used as C-based and N-based bisnucleophiles. We have developed a one-step synthetic approach to 2-fluoro-2-pyrrolines derivatives through simple base mediated cascade reaction. Simultaneously, we achieved nine kinds of different transformations of the representative 2-fluoro-2-pyrroline, which fully demonstrated synthetic utilities of 2-fluoro-2-pyrrolines.In the third part of this dissertation, we examined the reaction of 2-trifluoromethyl-1,3-conjugated enynes with N-acetylated 2-Aminomalonates. The reactions could deliver two distinct types of products depending on substrates, i. e. 4-trifluoromethyl pyrrolidines derivatives, or gem-difluoro-1,3-conjugated enynes derivatives. Various functionalized 4-(difluoromethylene)-1,2,3,4-tetrahydropyridi-nes could be obtained in good yields via the gold(I)-catalysed intramolecular 6-endo-dig cyclization of the corresponding gem-difluoro-1,3-conjugated enynes under mild conditions.