An improved,efficient route to 2,2-difluoroethenylbenzenes

Treatment of vinylidene fluoride with tert-BuLi at ?115 °C gave a solution of F₂CCHLi]. Addition of Bu₃SnCl to this lithium reagent at ?110 °C gave an 88% isolated yield of F₂CCHSnBu₃. Reaction of F₂CCHSnBu₃ with substituted aryl iodides under Stille-Liebeskind conditions Pd(PPh₃)₄/Cu(I)I] at room temperature afforded the 2,2-difluoroethenylbenzines in good yield. In the absence of the Cu(I)I co-catalyst, no reaction occurred. This work provides the most efficient route for the conversion of aryl halides to 2,2-difluorostyrenes.