Phthalimide → 2-Phenyl-4-(4-phtalimidobut-1-yl)-1,3-dioxolane

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Reaktionsschritte

A solution of diethyl azodicarboxylate (8.6 g, 49.4 mmol) in 40 mL of THF was slowly added to a cold (ice bath) solution of 17 (10.0 g, 45.0 mmol), triphenylphosphine (13.0 g, 49.5 mmol) and phthalimide (7.3 g, 49.7 mmol) in 60 mL of THF. After being kept at ambient temperature overnight, the solution was concentrated and the residue was triturated with ether (˜150 mL) to precipitate triphenylphosphine oxide which was then removed by filtration. The filtrate was concentrated to give an oily residue which was chromatographed on silica eluting with 33% ethyl acetate in hexane. Concentration of the pure product fractions followed by drying under vacuum afforded 14.6 g (92%) of the desired product as a semi-solid (a mixture of diastereomers): 1H NMR (CDCl3, 300 MHz, ppm) 7.85 (m, 2H), 7.71 (m, 2H), 7.46 (m, 2H), 7.36 (m, 3H), 5.90 (s, 0.4H), 5.78 (s, 0.6H), 4.3-4.0 (m, 2H), 3.68 (m, 3H), 1.9-1.3 (m, 6H).

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