tert-Butyl 4-oxopiperidine-1-carboxylate → 1-Boc-4-Methylenepiperidine

Participants

Reaction Steps

To a cooled suspension of methyl triphenyl phosphonium bromide (47.0 g, 132 mmol) in THF (330 mL) was added n-BuLi (85.0 mL, 136 mmol). 1-Boc-4-piperidone (25.0 g, 125 mmol) was added via cannula as a solution in THF. The resulting mixture was kept at 0° C. and allowed to warm to r.t. over 2 h. The reaction mixture was cooled to 0° C. and quenched with saturated NH4Cl. The resulting precipitate was filtered off and the layers were separated. The remaining aqueous layer was extracted with Et2O and the combined organic layers were dried (MgSO4) and concentrated. The crude residue was purified (FCC) to give 4-methylene-piperidine-1-carboxylic acid tert-butyl ester (22 g, 91%)

Provenance & Evidence