Preparation And Application Of Fluorine-containing Organozinc Reagents

Organozinc reagent is one of the most important organometallics.Organozinc reagents represented excellent functionality compatibility in organic synthetic chemistry because of the high chemoselectivity.More importantly,they can undergo transmetalation with many transition metal salts or complex under mild conditions,and the new transition metal compounds can react with many organic electrophiles.The fluorine-containing organozinc reagent not only has the advantage of organozinc reagent,but also retains excellent chemical and thermal stability of fluorochemicals.It can be widely used in the synthesis of fluorine-containing compounds.The main work presented in this dissertation was the generation of trifluoroethylenylzine reagent by Zinc insertion.The optimized reaction conditions are obtained by screening preparation conditions as follow:S-06 as solvent,1:1.3 of n?CF₂=CFBr?:n?Zn?,40?of reaction temperature,initiator?,200ppm of moisture in the solvent.Under the conditions,product yield between 84.5%and 86.5%,higher than the reported yield of 77%.In the preparation of?,?,?-trifluorostyrenes,iodobenzene,bromobenzene and chlorobenzene coupled with trifluoroethylenylzine reagent in the presence of catalyst,respectively.Obviously,the optimized reaction condition of iodobenzene are PdCl₂ and PPh₃ as catalyst,1:1.1 of n?PhI?:n?CF₂=CFZnBr?,reaction temperature between 30?and 60?,1mol%of catalyst,3-6 h of reaction time.Under the conditions,product yield can reach 83%,higher than the literature reported yield of 74%.The?,?,?-trifluorostyrenes was extracted by vacuum distill and ice water extraction,and then purified by vacuum distillation to give 99%of productcontent.Finally,thereactionmechanismof?,?,?-trifluorostyrenes was discussed.