A solution of the product of Example 332B (1.00 g, 2.5 mmol) and triphenylphosphine (0.98 g, 3.75 mmol) in THF (10 mL) was heated at reflux for 4 hours. The reaction mixture was cooled to ambient temperature, water (0.45 mL) was added, and the reaction mixture was stirred for 18 hours. The reaction mixture was concentrated in vacuo and the residue was partitioned between water and ethyl acetate. The organic phase was washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo. Chromatography on silica gel (25% ethyl acetate-hexane, then 1% ammonia-ethyl acetate) gave the desired compound as a colorless oil (900 mg, 97%).
