A solution of 51 mg of 20-methyl-1α,3β-bis(methoxycarbonyloxy)-21-p-toluenesulfonyloxypregna-5,7-diene in 1 ml of diethyl ether was added dropwise, at -50° C. to -60° C., to a diethyl ether solution of diisoamylcopper lithium as prepared from 100 mg of cuprous iodide and 0.9 ml of 1.1N diethyl ether solution of isoamyllithium in 2 ml of diethyl ether. reaction mixture was poured into a cold aqueous solution of ammonium chloride and the resulting mixture was extracted with diethyl ether. The extract was washed with 10% aqueous ammonia, water and an aqueous solution of sodium chloride, dried over sodium sulfate and then concentrated. The residue was dissolved in 1 ml of methanol, 10 mg of potassium carbonate was added, and the resulting mixture was stirred at ambient temperature for 12 hours. The reaction mixture was poured into water and extracted with methylene chloride. The extract was washed with an aqueous solution of sodium chloride, dried over sodium sulfate and concentrated. The residue was washed with cold ethyl acetate to give 29 mg of cholesta-5,7-diene-1α,3β-diol.
