1: With N,N,N',N,-tetramethylethylenediamine; dimethyl sulfoxide; copper (I) trifluoromethane sulfonate benzene T=130 - 135°C; 18 h; 2: With hydrogenchloride in water; ethyl acetate pH=< 3; 3: With hydrogenchloride; sodium hydroxide more than 3 stages;

water; hydrogen bromide; acetic acid 24 h; Heating / reflux;