Methoxymethyl-triphenylphosphonium chloride → (Z)-tert-butyl 2-benzyl-4-(methoxymethylene)piperidine-1-carboxylate

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Reaction Steps

Potassium tert-butoxide (4.49 mL, 1M in THF) was added over about 5 minutes to (methoxymethyl)triphenylphosphonium chloride (1.42 g, 4.15 mmol) suspended in anhydrous THF (25 mL) at 0° C. The resulting suspension was stirred at about this temperature for about 45 minutes at which time, tert-butyl 2-benzyl-4-oxopiperidine-1-carboxylate (1.0 g, 3.46 mmol) dissolved in THF (5 mL) was added. The reaction mixture was allowed to warm to ambient and stir for another 6 h. The reaction was quenched by the addition of ammonium chloride solution and then taken up in EtOAc. After washing twice with water and once with brine, the organic portion was dried over magnesium sulfate, filtered and concentrated. The resulting semi-solid residue was purified via silica gel chromatography to give (Z)-tert-butyl 2-benzyl-4-(methoxymethylene)piperidine-1-carboxylate (375 mg, 34%). LCMS (APCI+) m/z 218.1 [M+H]+; Rt=4.51 min.

Provenance & Evidence