1: 1,1-dibromo-2-(pentafluorophenyl)ethene With n-butyllithium in hexane T=-78 - 20°C; Fritsch-Buttenberg-Wiechell rearrangement; 4 h; Inert atmosphere; 2: With magnesium bromide in hexane 0.25 h; Inert atmosphere; 3: carbon dioxide in hexane T=20°C;

(i) NiO2, benzene, (ii) aq. HCl; Multistep reaction;

1: (i) CuI, aq. NH3, EtOH, (ii) /BRN= 2051549/, Py, (iii) H2SO4, MeOH 2: (i) NiO2, benzene, (ii) aq. HCl View Scheme