sodium in diethyl ether byproducts: NaCCCH2CH2CH2CH3; the soln. of stannane was added to a suspn. of Na, the mixt. was stirred (5 h, 30-35°C), filtered under N2; the product was sepd. from filtrate by distn.;

boron trifluoride diethyl etherate; difluoro[4-(trifluoromethyl)phenyl]-λ(3)-bromane in dichloromethane T=-78 - 20°C; 5 h;

sulfuric acid 2.) RT; Yield given. Multistep reaction. Yields of byproduct given;