Cesium Hydroxide-Catalyzed Regioselective Synthesis Of (Z)-1-Arylseleno-2-arylthioalkenes

Organochalcogenide compounds have become attractive synthetic targets because of their good biological activity and their chemo-, regio- and stereoselectivity in oganic chemistry. Chalcogen atoms (S, Se, Te) exercise a stabilizing effect on carbanion bonding to them, which makes the organochalcogenide compounds can be carried out both nucleophilic and electrophilic reaction. While introducing two different chalcogen atoms on the same double bond, vinylic chalcogenide compounds with different organochalcogen group were obtained. The carbon-hetero bonds have different reactivity, and they can be cleaved selectively. These compounds can be used as efficient intermidiates in selective synthesis of multi-substituted olefins. Till now, there are few works on the synthesis of these compounds. Most focuss on the synthesis of (Z)-1,2-arylthio olefins and (Z)-1,2-arylseleno olefins. Here, We report a highly chemo-, regio-and stereoselective synthetic method for (Z)-vinylic selenosulfides in a one-pot reaction of terminal alkynes, diaryl disulfides anddiaryl diselenides catalyzed by cesium hydroxide monohydrate. The works of this thesis are listed as follows:(1) The reaction of propargyl alcohol and diphenyl disulfide-diphenyl diselenide binary system was used as a model reaction to explore the influence of catalysts, solvent, time and amount of catalyst to the reaction. Optimal conditions are obtained as follows:CsOH, DMF, room temperature,20 h. And the reactions of different propargyl alcohols and a variety of diaryl disulfides and diaryl diselenides were studied. All the reactions afford the corresponding products in the yield of 67%-86%, under optimal conditions.(2) The reaction of 3-phenyloxyl propargyl-2-en and diphenyl disulfide-diphenyl diselenide binary system was used as a model reaction to explore the influence of catalysts, solvent, time and amount of catalyst to the reaction. Optimal conditions are obtained as follows:CsOH, DMF, room temperature,20 h. And the reactions of different propargyl ethers and a variety of diaryl disulfides and diaryl diselenides were studied. All the reactions afford the corresponding products in the yield of 65%-75%, under optimal conditions.(3) The reaction of phenylacetylene and diphenyl disulfide-diphenyl diselenide binary system was used as a model reaction to explore the influence of catalysts, solvent, time and amount of catalyst to the reaction. Optimal conditions are obtained as follows:CsOH, DMF, room temperature,20 h. And the reactions of different phenylacetylenes and a variety of diaryl disulfides and diaryl diselenides were studied. All the reactions afford the corresponding products in good yield up to 93%, under optimal conditions.In this thesis, we report a highly chemo-, regio-and stereoselective synthetic method for (Z)-vinylic selenosulfides is described in a one-pot reaction of terminal alkynes, diaryl disulfides anddiaryl diselenides catalyzed by cesium hydroxide monohydrate. The advantages of the reaction include:stable and easily obtained materials, mild reaction conditions, high regioselectivity. This method provides a new way for the synthesis of (Z)-1-arylseleno-2-arylthio olefin compounds.All targetic compounds were characterized and confirmed by 1H NMR,13C NMR, MS and HRMS. The configurations of the desired products were confirmed by NOESY and crystal analysis.