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.

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.Figure optionsDownload as PowerPoint slideHighlights
► Pd(PPh3)4/Cu(I)I catalyzed coupling of F2CCHSnBu3 with substituted aryl iodides provide an efficient route to F2CCHAr-X.
► No reaction is observed in the absence of the Cu(I)I co-catalyst.
► F2CCHSnBu3 was prepared in 88% isolated yield from vinylidene fluoride.
► 2,2-difluoroethenylbenzenes also provide a useful route to 2,2-trifluoroethylbenzenes.