1alpha,3beta-Bis(tert-butyldimethylsilyloxy)-17-(tert-butoxycarbonylmethoxymethyl)androsta-5,7,16-triene → 1alpha,3beta-Bis(tert-butyldimethylsilyloxy)-17-(2-ethyl-2-hydroxybutoxymethyl)androsta-5,7,16-triene

Participants

Reaction Steps

A solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-17-(tert-butoxycarbonylmethoxymethyl)androsta-5,7,16-triene (175 mg, 0.266 mmol) in tetrahydrofuran (4 ml) was subjected to reaction with a 0.96M ethylmagnesium bromide/tetrahydrofuran solution (3 ml, 2.88 mmol) using a procedure similar to that of Example 27(2) (external temperature of −30° C. for 1.5 hours), worked up and purified by preparative thin layer chromatography (3 sheets (each 0.5 mm thickness), hexane:ethyl acetate=20:1, developed twice, hexane:ethyl acetate=15:1, developed twice, and hexane:ethyl acetate=10:1, developed once) to give the titled compound (139.5 mg, 81%) as a colorless oil.

Provenance & Evidence