1: 96 percent / p-toluenesulfonic acid / 1 h / Heating 2: 70 percent / carbon tetrabromide, triphenylphosphine / diethyl ether / 3 h View Scheme

1: 96 percent / p-toluenesulfonic acid / 1 h / Heating 2: 92 percent / Jones reagent / acetone 3: oxalyl chloride / 0.5 h / Ambient temperature 4: N-hydroxypyridine-2-thione sodium salt, 4-dimethylaminopyridine, bromotrichloromethane / CCl4 / 0.25 h / Heating 5: 73 percent / lithium aluminium hydride / tetrahydrofuran / Heating View Scheme