boron tribromide in dichloromethane T=-78 - 20°C;

1.1: 100 percent / K2CO3 / dimethylsulfoxide / 2 h / 20 °C 2.1: 3-tert-butyl-4-hydroxy-5-methylphenyl sulfide; m-CPBA / CH2Cl2 / Heating 2.2: 71 percent / aq. NaOH / ethanol / 2 h 3.1: NaH / dimethylformamide / 0 °C 3.2: 51 percent / dimethylformamide / 160 - 170 °C 4.1: 15 percent / polyphosphoric acid / xylene / 0.5 h / Heating 5.1: 71 percent / BBr3 / CH2Cl2 / -78 - 20 °C View Scheme

1.1: 3-tert-butyl-4-hydroxy-5-methylphenyl sulfide; m-CPBA / CH2Cl2 / Heating 1.2: 71 percent / aq. NaOH / ethanol / 2 h 2.1: NaH / dimethylformamide / 0 °C 2.2: 51 percent / dimethylformamide / 160 - 170 °C 3.1: 15 percent / polyphosphoric acid / xylene / 0.5 h / Heating 4.1: 71 percent / BBr3 / CH2Cl2 / -78 - 20 °C View Scheme

1.1: NaH / dimethylformamide / 0 °C 1.2: 51 percent / dimethylformamide / 160 - 170 °C 2.1: 15 percent / polyphosphoric acid / xylene / 0.5 h / Heating 3.1: 71 percent / BBr3 / CH2Cl2 / -78 - 20 °C View Scheme

1: 15 percent / polyphosphoric acid / xylene / 0.5 h / Heating 2: 71 percent / BBr3 / CH2Cl2 / -78 - 20 °C View Scheme