18-Crown-6 → HCID 57256948, compound

Participants

Reaction Conditions

Reaction Steps

xvii)—A mixture of (3β,5α,20S)-3-[(1-ethoxyethyl)oxy]-4,4-dimethylpregna-8,14-dien-20-ol (17; 1.65 g), dry toluene (115 ml), potassium t-butoxide (5.68 g), 18-crown-6 (0.99 g) and 4-bromo-2-methyl-2-butene (4.44 ml) was heated at 70° C. for 1 h. After cooling, the reaction mixture was poured into water and the product extracted into ethyl acetate. The combined organic phases were washed with water and with brine, dried over sodium sulfate, and concentrated under reduced pressure to give (3β,5α,20S)-3-[(1-ethoxyethyl)oxy]-4,4-dimethyl-22-oxacholesta-8,14,24-triene (compound 18; 2.30 g), which was used in the following step without further purification.

Provenance & Evidence