Sodium borohydride → HCID 57857007, compound

Participants

Reaction Conditions

Reaction Steps

To a stirring solution consisting of (3aR,4R,5R,6aS)-4-((E)-3-(benzo[b]thiophen-2-yl)-3-oxoprop-1-enyl)-2-oxohexahydro-2H-cyclopenta[b]furan-5-yl benzoate (4a, limiting reagent) in 2:1 THF-methanol (0.1 M) cooled to −40° C. is added CeCl3 heptahydrate. The reaction mixture is subsequently cooled to −78° C. and sodium borohydride (2 molar equivalents) is added and the solution is stirred for 1.5 hours. The reaction is quenched by the addition of acetone at −60° C. followed by the addition of a saturated aqueous ammonium chloride solution as the reaction mixture slowly warms to room temperature. The reaction mixture is diluted with brine and acidified with a small amount of 5% aqueous KHSO4. The product is extracted with ethyl acetate twice and the combined organic layers are dried over sodium sulfate, filtered, and evaporated under reduced pressure. The crude product is purified by flash chromatography on regular silica gel eluted with hexanes-ethyl acetate to afford the title intermediate 5a.

Provenance & Evidence