Potassium Hydroxide → tert-Butyl 1-oxa-6-azaspiro(2.5)octane-6-carboxylate

Participants

Reaction Steps

To a solution of 44.9 g (0.225 mol) of 4-oxo-piperidine-1-carboxylic acid tert-butyl ester (31) in 500 ml acetonitrile was added successively 59.5 g (0.27 mol) trimethyl sulphoxonium iodide and 18.9 g (0.338 mol) fine crushed potassium hydroxide. The reaction mixture was vigorously stirred for two days under a nitrogen atmosphere at room temperature. After complete conversion the solvent was evaporated in vacuo and the residue was taken up in dichloromethane. The organic layer was washed with aqueous citric acid solution (6×), dried over sodium sulphate and concentrated in vacuo. This crude product was used without further purification for the next step (43.5 g, 0.204 mol, 90.6% yield).

Provenance & Evidence