1: 1,1,2,2-tetra(4-fluorophenyl)ethane With trifluorormethanesulfonic acid; tetra-n-butylammonium tetrafluoroborate in dichloromethane T=-78°C; Electrolysis; 2: allyl-trimethyl-silane in dichloromethane T=-78°C; 0.333333 h;