ozone 1.) dichloromethane, -78 deg C, 0.5 h, 2.) carbon tetrachloride, reflux, 0.5 h; Yield given. Multistep reaction;

1: 1.) benzene, room temp., 1 h, 2.) reflux., 20 h 2: 1.) ozone / 1.) dichloromethane, -78 deg C, 0.5 h, 2.) carbon tetrachloride, reflux, 0.5 h View Scheme

tetrafluoroboric acid; mercury(II) dithiocyanate 1.) CH2Cl2, 40 deg C, 24 h, 2.) CH2Cl2, Et2O, 30 min; Yield given. Multistep reaction. Yields of byproduct given;