carbon tetrabromide; triphenylphosphine in dichloromethane 0 deg C, 30 min, 0 deg C to rt;

1: 97 percent / NaBH4 / methanol; tetrahydrofuran; diethyl ether / 0 deg C, 30 min, 0 deg C to rt, 2 h 2: 86 percent / CBr4, PPh3 / CH2Cl2 / 0 deg C, 30 min, 0 deg C to rt View Scheme

1: boric acid trimethyl ester; boron trifluoride diethyl etherate; borane-pyridine complex; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / 3 h / 20 °C 2: carbon tetrabromide; triphenylphosphine / dichloromethane / 3 h / 0 - 20 °C View Scheme