p-Toluenesulfonic acid → tert-Butyl 3-hydroxy-4-oxopiperidine-1-carboxylate

Participants

Reaction Steps

tert-Butyl 3-hydroxy-4,4-dimethoxypiperidine-1-carboxylate from Example 44A (5.24 g, 20.1 mmol) was dissolved in acetone (100 mL), and p-toluene sulfonic acid (173 mg, 1.00 mmol) was added. The mixture was stirred at rt for 3 days, then filtered, and the filtrate was concentrated. The residue was dissolved in tert-butyl methyl ether and extracted with satd. aqueous sodium bicarbonate solution. The organic layer was dried over sodium sulfate, and the solvent was removed in vacuo to yield 4.67 g of an oil (64% purity, 69% yield), which was used in the next step without further purification.

Provenance & Evidence