Br2 in sulfolane addn. of (CF3)2Pb(CH3)Br (8 mmol) in portions to (CF3)2Cd*D (4 mmol) in sulfolane at 70°C with stirring; condensing off mixt. of (CF3)2Pb(CH3)2 and (CF3)3Pb(CH3) (ratio 1/1.5); addn. of amt. of Br2 corresponding to (CF3)2Pb(CH3)2;; pptn. after 5 d at -25°C; condensing off from ppt.;;