m-Chloroperbenzoic acid → HCID 67924634, compound

Participants

Reaction Steps

To a solution of 3β-benzoyloxy-4,4-dimethyl-5α-cholest-8,14-diene (5.0 g, 10.2 mmol) in diethyl ether solution (300 mL) and 0.5M aqueous sodium bicarbonate (300 mL) was added meta-chloro-perbenzoic acid (2.44 g, 11.3 mmol) (Aldrich). After 30 min, the ether fraction was separated from the sodium bicarbonate layer and the aqueous fraction was repeatedly extracted with diethyl ether (5×500 mL). The organic fractions were combined, washed with brine (1×100 mL), dried over magnesium sulfate, filtered, and concentrated in vacuo to about 150 ml. This ether solution of 38a was promptly cooled (0°) and treated dropwise with boron trifluoride etherate (26 mL, 22.5 mmol (Aldrich). After 30 min, the reaction was quenched with ice water (200 mL) and the aqueous phase was reextracted with ether (3×100 mL). The combined ether fractions were extracted with saturated sodium bicarbonate solution (1×200 mL), dried over anhydrous magnesium sulfate, filtered, and concentrated in vacuo. The residue was crystallized from isopropanol (75 mL) to afford 4.10 g of 3β-benzoyloxy-4,4-dimethyl-5β-cholest-8-en-15-one (Compound 40a) in 75% yield.

Provenance & Evidence