Phosphonium, [2-(1,3-dioxolan-2-yl)ethyl]triphenyl-, bromide (1:1) → (1S,3aS,7aR)-1-acetoxymethyl-5-((Z)-2-(1,3-dioxolan-2-yl)ethyliden]-7a-methylperhydroinden-3a-ol

Participants

Reaction Conditions

Reaction Steps

To a suspension of 26.0 g of [2-(1,3-dioxolan-2-yl)ethyl]-triphenylphosphonium bromide in 300 ml of anhydrous THF, cooled at -25° C., 36 ml of 1.6N n-butyllithium in n-hexane were added, under a nitrogen atmosphere. After stirring for 1 hr, a solution of 5.0 g of (1S,3aS,7aR)-1-acetoxymethyl-3a-hydroxy-7a-methyl-5-perhydroindenone in 50 ml of anhydrous THF was added and the resulting mixture was stirred at -20° C. for 4 hrs, then at room temperature per 3 hrs. The reaction mixture was diluted with water and extracted with ethyl acetate. The organic layer was dried over sodium sulfate and evaporated to dryness under reduced pressure. The residue was purified by flash-chromatography (SiO2) with methylene chloride/acetone 95:5 as the eluant to give 1.88 g of (1S,3aS,7aR)-1-acetoxymethyl-5-[(Z)-2-(1,3-dioxolan-2-yl)ethyliden]-7a-methyl-perhydroinden-3a-ol and 1.46 g of (1S,3aS,7aR)-1-acetoxymethyl-5-[(E)-2-(1,3-dioxolan-2-yl)ethyliden]-7a-methylperhydroinden-3a-ol as pale yellow oils.

Provenance & Evidence