A 1:1 methanol:methylene chloride solution (40 mL) of (3aR,4R,5R,6aS)-5-(benzoyloxy)hexahydro-2H-cyclopenta[b]furan-2-one-4-carbaldehyde (1) (purchased from Cayman Chemical Company, Ann Arbor, MI) (3.5 g, 12.8 mmol) in a 1:1 methanol:dichloromethane solution (40 mL). After 25 min of reaction, the reaction was quenched by careful addition of saturated aqueous citric acid solution (60 mL). The mixture was extracted with ethyl acetate (3 × 40 mL) and the organic layers were combined and washed sequentially with water (2 × 80 mL) and saturated saline (2 × 80 mL). The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give the target compound 2 (2.43 g, 69% yield).
