Synthesis Of Unsaturated Hydrocarbons Trifluoromethyl Thio(seleno)ethers Via Copper(Ⅰ)-promoted Trifluoromethylthiolation And Trifluoromethylselenolation Of Unsaturated Hydrocarbons

The incorporation of trifluoromethylthio(-SCF3)into organic molecules can significantly improve the physical,chemical and physiological properties of the compounds owing to their strong electron-withdrawing effect and high hydrophobicity parameter,and this will make the applicational value of the parent compounds get a great improvement in the fields of material,medicine,military and so on.In the numerous of fluorine-containing organic compounds,in recent years,trifluoromethylthio and trifluoromethylselen organic compounds draw great attentionsThree stypes of reactions for synthesizing Trifluoromethyl Thioethers and trifluoromethyl selenoethers have been reported:nucleophilic,electrophilic,radical trifluoromethylation of disulfides,thiols,thiocyanates,and thiolates with a trifluoromethylation reagent However,these reactions are generally limited by toxic and expensive reagents,the preparation of sulfur-containing precursors,or narrow substrate scope.Transition metal catalyzed reactions provide much green ideas of synthesis of fluorine-containing organic compounds,and it has been a hot field to synthesis the trifluoromethylthio trifluoromethylselen group-containing compounds in a more economical,more environmental and more efficient method.Synthesis of Allylic and Propargylic Trifluoromethyl Thioethers via Copper(I)-Catalyzed Trifluoromethylthiolation of Allylic Bromides and Propargylic Chlorides and Synthesis of propargylic and allylic trifluoromethyl selenoethers by copper-mediated trifluoromethylselenolation of propargylic chlorides and allylic bromides.Part one:An efficient method for copper(I)-catalyzed trifluoromethylthiolation of allylic bromides with elemental sulfur and CF3SiMe3 is reported.This transformation can be significantly accelerated in the presence of 2 equiv of 18-crown-6.The reaction affords desired products in moderate to excellent yields with high stereo-and regioselectivity.This method is tolerant a number of functional groups,and provides facile access to a wide variety of allylic trifluoromethyl thioethers.The copper(Ⅰ)-catalyzed trifluoromethylthiolation of propargylic chlorides was also investigated.A plausible mechanism involved an allylcopper(Ⅲ)intermediate is proposed.The reaction of copper source with CF3SiMe3,elemental sulphur,and KF in the presence of ligands would easily give the copper(Ⅰ)trifluoromethylthiolate complex.Then,the oxidative addition of allylic halides to Ⅰ affords the allylcopper(Ⅲ)species.The subsequent reductive elimination of the allylcopper(Ⅲ)gives the desired trifluoromethylthiolated product and generates[phenCuBr].The intermediate is then regenerates by reaction of[phenCuBr]with CF3SiMe3,S8,and KF.Part two:we have developed the method for the synthesis of propargylic and allylic trifluoromethyl selenoethers via the copper-mediated trifluoromethylselenolation of propargylic chlorides and allylic bromides.A variety of propargylic and allylic trifluoromethyl selenoethers can be obtained in moderate to good yields.A purely free radical pathway is not involved in the present reaction.The scope of the reaction and potential synthetic applications of the copper-mediated trifluoromethylselenolation are currently under investigation.