Water → (1S,5R,6R,7R)-6-(3-oxo-5-phenyl-1E-pentenyl)-7-((4-phenylbenzoyl)oxy)-2-oxabicyclo(3.3.0)octan-3-one

Participants

Reaction Steps

A solution of pyridine sulfur trioxide (0.60 g) in DMSO (7.0 mL) was added dropwise to a stirred solution of compound [5a] (0.60 g) and triethylamine (0.80 g) in dichloromethane (8 mL) at −5-0° C. The mixture was stirred at the same temperature for 1 hour (TLC monitoring) and poured into cold water (30 mL). The mixture was stirred for 10 min at 0-5° C. The organic layer was separated, the water layer was extracted with dichloromethane (3×10 mL). The combined organic layers were washed with brine (3×20 mL), dried over sodium sulfate, filtered and evaporated under reduced pressure. A solution of the residue in methanol (2 mL) was cold to −10° C. and kept at the same temperature for 3 hours. The precipitated crystals were filtered, washed on filter with cold methanol (2×2 mL) and dried under reduced pressure to a constant weight to give 0.50 g (83.7% yield) of crystalline compound [4a].

Provenance & Evidence