Preparation of β,β-Difluoro-α-(trifluoromethyl)styrenes by Palladium-Catalyzed Coupling of Aryl Iodides with Pentafluoropropen-2-ylzinc Reagent

Article abstract of DOI:10.1021/jo00057a032

Substituted aromatic iodides are functionalized by pentafluoropropen-2-ylzinc, CF3C(ZnX)=CF2 (X = Br, I, or CF2=CCF3-), in the presence of Pd(PPh3)4 to give the corresponding arenes in good yields.This is particularly attractive for the preparation of title styrenes substituted with groups such as -NO2 or CO2R, which are incompatible with organomagnesium reagents.The best yields of the title styrenes with electron-donating substituents were obtained in DMF.For electron-withdrawing substituents, the best results were achieved in triglyme.A correlation was observed between Hammett ? constants and 19F NMR chemical shifts (R = 0.93-0.99, n = 8) and ²J_F-F coupling constants (R = 0.94, n = 8).