Methyl vinyl ketone → Benzyl 9-oxo-3-azaspiro(5.5)undec-7-ene-3-carboxylate

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Reaction Steps

A solution of 0.98 g (3.96 mmol) benzyl 4-formylpiperidine-1-carboxylate (prepared by the method from Eur. J. Med. Chem. 1991, 26, 625) and 0.28 g (4.0 mmol) 3-buten-2-one in a mixture of 1 ml methanol and 1 ml water was added dropwise to a boiling solution of 0.015 g (0.27 mmol), potassium hydroxide in 1 ml methanol. After 1 hour heating with reflux the cooled mixture was poured into 50 ml water, and it was extracted with tert.-butylmethylether. The organic layer was dried over sodium sulfate and concentrated under reduced pressure. The title compound was obtained from the remaining oil by HPLC on silica gel with hexane/acetone 4:1.

Provenance & Evidence