Phosphonium, [2-(1,3-dioxolan-2-yl)ethyl]triphenyl-, bromide (1:1) → Phenylmethyl 3-[2-(1,3-dioxolan-2-yl)ethylidene]azetidine-1-carboxylate

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Reaction Conditions

Reaction Steps

Potassium tert-butoxide (1.393 g, 12.4 mmol) and [2-(1,3-dioxolan-2-yl)ethyl]-triphenylphosphonium bromide (5.51 g, 12.4 mmol) were stirred in ether (30 mL) at ambient for 1 h. Phenylmethyl 3-oxoazetidine-1-carboxylate (1.025 g, 5.0 mmol), prepared using procedures similar to those described in Reference 3, was added and the mixture was stirred at 35° C. for 6 h and then at ambient for 4 days. Mixture was filtered through celite and the solid was washed with ether. The filtrate was washed with water, brine, dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. Column chromatography (silica gel, 20% ether in hexanes) gave phenylmethyl 3-[2-(1,3-dioxolan-2-yl)ethylidene]azetidine-1-carboxylate (220 mg, 0.761 mmol, 15% yield): 1H NMR (400 MHz, CDCl3): 7.39-7.28 (m, 5H), 5.43-5.35 (m, 1H), 5.11 (s, 2H), 4.89 (t, 1H), 4.56 (br d, 4H), 4.00-3.92 (m, 2H), 3.91-3.83 (m, 2H), 2.27 (br t, 2H).

Provenance & Evidence