High Region-and Stereo-Selective Synthesis Of Functional Alkene Promoted By CsOH

CsOH is a supper inorganic alkali,which can dissolves well and stably in dipolar aprotic solvent(THF,DMSO,NMP,DMF,DCM,DMAC).Nucleophilic anion can be produced throug the reaction between CsOH and corresponding weak organic acid in air.The organic reaction promoted by cesium hydroxide often has characteristics of environmentally-benign,the simplicity of operator,mild reactive conditions,easy post-processing and so on.Tegafur is a antitumor drug widely applied,but it has certain side effect in the clinical practice,we designed to link functional group of Se,S with Tegafur baseing on that organosulphur compouds including functional groups have biological activity and Se is a neccesary trace element in body,expecting either improvement of the drug effect and reduction of the side effect or application in the deeper study of structure-optimization and pharmacological action as a intermediate.We studyed the reaction between 3-[N¹-(2-furyl)-N³-(5-fluorouracil)]-1-allylene and diaryl disulf ides or diaryl diselenides catalyzed by CsOH.The experimental result indicated that we obtained the high stereoselective(Z)-1,2-diaryl diseleno(or thiol)-3-[N¹-(2-furyl) -N³-(5-fluorouracil)]-1-propylene,and the production rate is 80～85%.1-arylseleno-2-diarylthio-1-alkene are important function materials and import ant intermidiate in synthsis because of the different reactive activity of the two heteroatom linking to the double bond by additional reaction,it can also compose stabe complexes with transition metals.The taditional synthsise of these compounds reported in previous articles usually suffer multistep reaction via terminal alkyne as start materials react with diaryl disulfides or diaryl diselenides under the condition of illumination or n-BuLi or catalyzed by transition metals,but these methods uauslly can't be used widely because of their low yield,poor selectivity and rigorous operational condition(anhydrous and oxygen-free).In our study,diaryl selenosul fides react with terminal alkyne catalyzed by CsOH in DMF,and arylthio- and arylseleno- are linked to the double-bond simultaneously by one step.The experimental result indicated that we found a convenient method under mildcondition, with high yield,especialy high stereoselectivity.Alkenylphosphines play an important role in synthesizing organophosphorus com pounds as a intermediate product,they are also indispensable as ligands for transit ion-metal catalysts.However,their application is limited because of the lack of a simple and convenient procedure for their synthesis.The generally methods for syn thesis of alkenylphosphines include:the reaction of halophosphines with alkenylma gnesium or lithium derivatives and phosphide anion with alkenyl halides;radical chains reactions;the direct addition of secondary phosphines to alkynes catalyzed by transition-metal.However,there are some disadvantage in these methods,for examp le,the cost of reagent is expensive;the product is hard to separated;the yield is very low,and so on.We study that CsOH react with diphenylphosphine in DMF under nitrogen atmosphere to get Ph₂P^-Cs⁺,then react with terminal alkyne.The experimental result indicated that high region- and stereo-selective alkenylphosphines can be got by two steps- "one pot" reaction.