boron tribromide in dichloromethane 4 h; Ambient temperature;

1.1: NaH / dimethylformamide / 2 h / 0 - 20 °C 1.2: dimethylformamide / 3 h / 0 - 20 °C 2.1: 90 percent / Pd(dba)2; 1,1'-bis(diphenylphosphino)ferrocene / tetrahydrofuran / 5 h / 65 °C 3.1: LiOH / H2O; methanol / 5 °C 4.1: AgNO3 / acetone / 24 h / 20 °C 5.1: 86 percent / BBr3 / CH2Cl2 / 7.5 h / 20 °C View Scheme

1: 1.) n-BuLi, TMEDA / 1.) n-hexane, 60 deg C, 5 h, 2.) n-hexane, a.) -78 deg C, 1 h, b.) RT, overnight 2: 74 percent / tetrabutylammonium permanganate / pyridine / 2 h / Ambient temperature 3: 78 percent / SOCl2 / benzene / 0.5 h / 60 - 70 °C 4: 97 percent / BBr3 / CH2Cl2 / 4 h / Ambient temperature View Scheme

1: 1.) n-BuLi, TMEDA / 1.) n-hexane, 60 deg C, 5 h, 2.) n-hexane, a.) -78 deg C, 1 h, b.) RT, overnight 2: 74 percent / tetrabutylammonium permanganate / pyridine / 2 h / Ambient temperature 3: 78 percent / SOCl2 / benzene / 0.5 h / 60 - 70 °C 4: 97 percent / BBr3 / CH2Cl2 / 4 h / Ambient temperature View Scheme

toluene-4-sulfonic acid 1.) THF, -30 deg C, 2.) benzene, reflux; Yield given. Multistep reaction;