1: With isopropylmagnesium chloride in tetrahydrofuran T=0 - 20°C; 1 h; 2: With sulfur dioxide in tetrahydrofuran T=-40°C; 0.5 h; 3: With hydrogenchloride; sulfuryl dichloride more than 3 stages;

chlorosulfonic acid in dichloromethane 3 h; -78 deg C to room temperature;