Tin tetrachloride → 1'-Trifluoroacetyl-6-(propanoyl)-spiro[3,4-dihydrobenzopyran-2,4'-piperidine]

Participants

Reaction Conditions

Reaction Steps

A mixture of 1′-trifluoroacetyl-spiro[3,4-dihydrobenzopyran-2,4′-piperidine] (1.49 g, 4.98 mmol) and propanoyl chloride (0.4 mL, 5 mmol) in methylene chloride (13 mL) was cooled at 10° C. Tin tetrachloride (1M solution in methylene chloride) (0.76 mL, 6.5 mmol) was added at 10° C. and stirred at 10° C. for 20 min then quenched with aqueous 2N HCl at 0° C. The aqueous layer was extracted twice with methylene chloride and the combined organics was washed with brine, dried (Na2SO4), filtered, and concentrated to provide a crude product. The crude product was purified by ISCO (80 g column) chromatography using 17 to 35% EtOAc in hexane to produce 1′-trifluoroacetyl-6-(propanoyl)-spiro[3,4-dihydrobenzopyran-2,4′-piperidine] (1.42 g, 81%),

Provenance & Evidence