Methyl vinyl ketone → Tert-butyl 9-oxo-3-azaspiro[5.5]undec-7-ene-3-carboxylate

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Reaction Conditions

Reaction Steps

3 N KOH in ethanol (7.5 ml) was added to mixture of tert-butyl 4-formylpiperidine-1-carboxylate (60.0 mmol, 1.0 eq.) and methyl vinyl ketone (70.0 mmol, 1.3 eq.) in THF (100 ml) at 0° C. and the mixture was then stirred at 25° C. for 16 h. The solvent was evaporated under reduced pressure and the residue diluted with water (100 ml) and KHSO4 solution at 0° C. The aqueous layer was extracted with MC (2×150 ml). The combined organic layers were washed with brine (100 ml) and dried over sodium sulfate. The solvent was evaporated under reduced pressure and the crude product was purified by silica gel column chromatography eluting with 10-12% ethyl acetate in hexanes to give the desired product as a light brown sticky solid. Yield: 25%

Provenance & Evidence