Dibenzo-18-crown-6 → 1alpha,3beta-Bis(tert-butyldimethylsilyloxy)-20-hydroxy-20-methylpregna-5,7,16-triene

Participants

Reaction Steps

1α,3β-Bis(tert-butyldimethylsilyloxy)-20-hydroxy-20-methylpregna-5,7,16-triene (261.4 mg, 0.456 mmol), potassium hydride (35% in oil, 0.53 ml, 4.625 mmol), dibenzo-18-crown-6 (165 mg, 0.458 mmol), toluene (0.75 ml) and 1,2-epoxy-2-ethylbutane (450 mg, 4.493 mmol) were subjected to reaction using a procedure similar to that of Example 21(1) (at external temperature of 95° C. for 2 hours and 10 min.), worked up and the thus obtained residue was purified by column chromatography (hexane:ethyl acetate=10:1) and preparative thin layer chromatography (1 sheet (0.5 mm thickness), hexane:ethyl acetate=20:1, developed twice) to give the titled compound (32.0 mg, 10%) and 1α,3β-bis(tert-butyldimethylsilyloxy)-20-hydroxy-20-methylpregna-5,7,16-triene (138.5 mg, 53%), each as a colorless oil.

Provenance & Evidence