1: tetra-n-butyl ammonium hydrogen sulfate, NaOH / CH2Cl2; H2O / 16 h / Ambient temperature 2: LiBu / tetrahydrofuran; hexane / 0.33 h / -78 °C 3: p-TosOH / 1 h / 190 °C 4: 480 mg / BBr3 / CH2Cl2 / 1) -78 deg C, 2) -78 deg C to r.t. overnight View Scheme

1: p-TosOH / 1 h / 190 °C 2: 480 mg / BBr3 / CH2Cl2 / 1) -78 deg C, 2) -78 deg C to r.t. overnight View Scheme

1: LiBu / tetrahydrofuran; hexane / 0.33 h / -78 °C 2: p-TosOH / 1 h / 190 °C 3: 480 mg / BBr3 / CH2Cl2 / 1) -78 deg C, 2) -78 deg C to r.t. overnight View Scheme

1: LDA / tetrahydrofuran; hexane / 1 h / -78 °C 2: p-TosOH / xylene / 5.5 h / Heating 3: tetra-n-butyl ammonium hydrogen sulfate, NaOH / CH2Cl2; H2O / 16 h / Ambient temperature 4: LiBu / tetrahydrofuran; hexane / 0.33 h / -78 °C 5: p-TosOH / 1 h / 190 °C 6: 480 mg / BBr3 / CH2Cl2 / 1) -78 deg C, 2) -78 deg C to r.t. overnight View Scheme

1: p-TosOH / xylene / 5.5 h / Heating 2: tetra-n-butyl ammonium hydrogen sulfate, NaOH / CH2Cl2; H2O / 16 h / Ambient temperature 3: LiBu / tetrahydrofuran; hexane / 0.33 h / -78 °C 4: p-TosOH / 1 h / 190 °C 5: 480 mg / BBr3 / CH2Cl2 / 1) -78 deg C, 2) -78 deg C to r.t. overnight View Scheme

boron tribromide in dichloromethane 1) -78 deg C, 2) -78 deg C to r.t. overnight;

1: 50 percent / I2 / benzene / 48 h / Ambient temperature 2: 480 mg / BBr3 / CH2Cl2 / 1) -78 deg C, 2) -78 deg C to r.t. overnight View Scheme