Dimethyl Sulfoxide → 1-Boc-4-Methylenepiperidine

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Reaction Steps

Methyltriphenylphosphonium bromide (9.5 g, 26.7 mmol) was dissolved in THF (33 mL). Sodium hydride (0.675 g, 26.7 mmol) was added portionwise followed by DMSO (33 mL). After stirring for 10 minutes, a solution of tert-butyl 4-oxopiperidine-1-carboxylate (5.0 g, 25 mmol) in THF (25 mL) was added dropwise. The resulting suspension was stirred at room temp for 30 minutes. Water and ethyl acetate were added and the organic phase was washed with aqueous NaHCO3 and brine and was dried (Na2SO4), filtered, and concentrated. The colorless oil was triturated with diethyl ether and the resulting solids were removed by filtration. Concentration of the solvent gave an oil that was purified by flash chromatography eluting with 30%–50% diethyl ether/hexane to provide the desired product as a colorless oil (2.69 g, 55% yield). 1H NMR (300 MHz, CDCl3) δ: 4.70 (2H, s), 3.38 (4H, t, J=5.7 Hz), 2.14 (4H, t, J=5.8 Hz), 1.43 (9H, s).

Provenance & Evidence