1: 1-bromo-4-iodo-2-(trifluoromethyl)benzene With n-butyllithium in diethyl ether; hexane T=-70°C; 0.5 h; Inert atmosphere; 2: With tri-isopropoxy-borane in diethyl ether; hexane T=-70°C; 0.25 h; 3: carbon dioxide Further stages;