1: 240 mg / BCl3 / CH2Cl2 / 4.5 h / Ambient temperature 2: toluene-p-sulphonic acid monohydrate / dimethylformamide / 82 h 3: 146 mg / pyridinium chlorochromate, sodium acetate / CH2Cl2 / 4 h 4: 59 mg / acetic acid (aq) / 24 h / Heating 5: 6.5 mg / LiI / hexamethylphosphoric acid triamide / 20 h / Heating View Scheme