Diisopropylamine → HCID 86739148, compound

Participants

Reaction Steps

To a solution of 1.0 mL of diisopropylamine in 3 mL of tetrahydrofuran at -30° C. was added 3.82 mL (0.0061 mol) of 1.6 M of butyllithium in hexane. After stirring for 0.5 hr, 3.03 g (0.0056 mol) of [1α,3β]-1,3-bis[(tetrahydro-2H-pyran-2-yl)oxy]pregn-5-en-21-oic acid ethyl ester in 30 mL of tetrahydrofuran was added dropwise to yield the lithium enolate of [1α,3β]-1,3-bis[tetrahydro-2H-pyran-2-yl)oxy]pregn-5-en-21-oic acid ethyl ester. The mixture was stirred for 1 hr at -30° C. and cooled to -70° C. A solution of 2.30 g (0.0068 mol) of 4-(1-ethoxyethoxy)-3,3-difluoro-1-iodo-4-methylpentane in 5 mL of hexamethylphosphoramide was added dropwise. The mixture was stirred at -70° C. for 1 hr and was allowed to warm to 25° C. and stir for 1 hr. The mixture was then diluted with 9:1 hexane-ether. The solution was washed with water, and saturated brine. The organic phase was dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. The residue was purified by column chromatography on 0.06-0.20 mm silica gel to give [1α,3β]-1,3-bis[(tetrahydro-2H-yran-2-yl)oxy]-25-(1-ethoxyethoxy)-24,24-difluorocholest-5-en-21-oic acid ethyl ester, [α]D20 +10° (c 1, CHCl3).

Provenance & Evidence