Copper(Ⅰ)-mediated Thioetherification And Trifluoromethylselenolation Of Halohydrocarbon

Transition-metal-catalytic carbon-heteroatom coupling reaction has a widespread application in organic synthesis and medical chemistry. Copper catalytic coupling reaction occupies a very important state and attracts considerable attention of scientists. Although copper catalytic C-S bond formation has been well developed, the reaction intermediates are still un-confirmed. The incorporation of fluorine-contained groups into organic molecules is a powerful strategy in the process of drug design; because their introduction could bring about remarkable changes in physical, chemical, and biological properties of the compounds. Developing an economical, efficient route of copper catalytic formation of C-SeCF3 is highly desirable.The thesis consists of three parts:Part I:[CuOtBu]4 was prepared by stirring CuCl with NaOtBu in THF; treatment of [CuOtBu]4 with the dative ligand and subsequent addition of arenethiol resulted in the formation of L-Cu-SAryl reagents. The complex, [(phen)Cu(μ-SC6H5)]2, has been successfully isolated and characterized by X-ray, NMR spectroscopy and elemental analysis. By 1H NMR tracking reaction for the yields and half-time of the reaction of p-iodotoluene with different complexes coordinated with diverse ligands; the results indicate that complexes containing the less sterically hindered ligand, reacts more quickly and affords higher yield. The intermediacy of such complexes in copper-catalyzed thiothericication of aryl halides was demonstrated by the reactivity with p-tolyl iodide and o-tolyl iodide to form two aryl thioethers with selectivities similar to that of copper-catalytic reactions conducted with the same two iodoarens; additionally supported by the results of whether copper is involved or not.Part Ⅱ:A family of air-stabled copper(I) trifluoromethylselenolate reagents were synthesized by the reaction of CuI with the Ruppert’s reagent (Me3SiCF3), KF, and elemental selenium in the presence of dinitrogen ligands in CH3CN at room teamperature. The reagents were all characterized by X-ray, NMR spectroscopy and elemental analysis. The reagent, [(bpy)CuSeCF3]2, was proven to be highly efficient for nucleophilic trifluoromethylselenolation of a broad range of (hetero)aryl halides; the yield was up to more than 95%, and the products could be easily isolated.Part III:A catalytic trifluoromethylselenolation of aryl and alkyl halides by a Cu(I) catalyst has been developed. The catalytic system is compatible with a wide range of functional groups, such as nitro, nitrile, methoxy, chloro, and amide. Silver plays an important role in promoting the reaction by transferring the SeCF3 group into copper species. A key intermediate, [(phen)Cu(SeCF3)]2, was successfully isolated and characterized by X-ray diffraction. Radical probe experiments indicate that the trifluoromethylselenolation are not in favor of the possible involvement of radical species.