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.