Ammonium Chloride → (3aR,4R,5R,6aS)-4-((E)-4,4-difluoro-3-oxo-1-octenyI)-2-oxo-5-(phenylmethoxy)hexahydro-2H-cyclopenta[b]furan

Participants

Reaction Steps

To a solution of dimethyl(3,3-difluoro-2-oxoheptyl)phosphonate (6.9 g, 26.5 mmoL) in MTBE (30 mL) was added LiOH.H2O (1.11 g, 26.5 mmoL) and the mixture was stirred under nitrogen for 1 h. A solution of (3aR,4R,5R,6aS)-hexahydro-2-oxo-5-(phenylmethoxy)-2H-cyclopenta[b]furan-4-carboxaldehyde (6, R1 is phenyl, and R2 and R3 are H, 6 g, 23.1 mmoL) in dichloromethane (30 mL) was added followed by NH4Cl (370 mg, 6.93 mmoL), 0.2 mL water and then the mixture was stirred for 12 h. After completion of the reaction, the reaction was then quenched with a saturated NH4Cl solution (12 mL). The organic layer was separated, washed with brine, dried over Na2SO4 and concentrated to dryness under vacuum. The crude material was further purified by column chromatography [25% ethyl acetate in heptanes] to yield (3aR,4R,5R,6aS)-4-((E)-4,4-difluoro-3-oxo-1-octenyl)-2-oxo-5-(phenylmethoxy)hexahydro-2H-cyclopenta[b]furan (7, R1 is phenyl, and R2 and R3 are H) in 56% yield.

Provenance & Evidence