Sodium hydride → 1alpha,3beta-bis(tert-butyldimethylsilyloxy)-20(S)-(4-methyl-4-triethylsilyloxy-2-pentynyloxy)pregna-5,7,16-triene

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Reaction Steps

A solution of 1α,3β-bis(tert-butyldimethylsilyloxy)-20(S)-hydroxypregna-5,7,16-triene (60.0 mg, 0.107 mmol), sodium hydride (60%, 17.1 mg, 0.428 mmol), 15-crown-5 (10 μl) and 1-bromo-4-methyl-4-triethylsilyloxy-2-pentyne (109 mg, 0.375 mmol) in tetrahydrofuran (1 ml) was stirred at 60° C. for 2 hours. The solution was cooled to room temperature and then taken into water and extracted with ethyl acetate. The extract was washed with brine and dried over magnesium sulfate, and the solvent was distilled off under reduced pressure. The resulting residue was purified by preparative thin layer chromatography (0.5 mm×2, hexane:ethyl acetate=40:1, developed once) to give the title compound as a colorless oil (82.4 mg, 99%).

Provenance & Evidence