sodium sulfide in N,N-dimethyl-formamide 2 h; Ambient temperature;

1: AlCl3, Br2 / diethyl ether / 0.5 h / Ambient temperature 2: sodium sulfide nonahydrate, methyltrioctylammonium chloride / hexane; H2O / 6 h / Ambient temperature View Scheme

1: 45 percent / Zn, titanium(IV) chloride / tetrahydrofuran / 12 h / Ambient temperature 2: 14.5 percent / p-toluenesulfonic acid monohydrate / benzene / 6.5 h / Heating View Scheme