A suspension of D7 (10 g, 44 mmol), phtalimide (10.29 g, 70 mmol) and triphenylphosphine (18.34 g, 70 mmol) in THF (150 mL) was cooled at 0° C., then a 40% solution of DEAD in toluene (31.94 mL, 70 mmol) was added. The mixture was stirred at room temperature for 3 hours, then water was added and the mixture was concentrated under vacuum; the residue was dissolved in DCM, washed with water and organics were evaporated. Cyclohexane (300 mL) and DCM (10 mL) were added, the precipitate was discarded and the filtrate was concentrated. The crude mixture was purified by silica gel column chromatography (cyclohexane/ethyl acetate=95:5 to 70/30) to give the title compound as a white solid. Yield (11 g, 71%).
