Tert-butyl 4-(5-bromo-2-fluorobenzoyl)-4-hydroxypiperidine-1-carboxylate → tert-Butyl 5-bromo-3-oxo-3H-spiro[benzofuran-2,4'-piperidine]-1'-carboxylate

Participants

Reaction Conditions

Reaction Steps

A 1 M solution of tBuOK (54.10 ml, 54.10 mmol) in THF was added to a solution of 4-(5-bromo-2-fluoro-benzoyl)-4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (14.5 g, 36.07 mmol) in THF (200 ml) and the mixture was stirred at 70° C. After 30 min, the solution was poured into ice water (150 ml) and the product was extracted with AcOEt. The combined organic layers were washed with water (50 ml), brine (50 ml), dried over Na2SO4, then filtered and evaporated to give a pale yellow oil. Purification by column chromatography (hexane/AcOEt: 80/20 to AcOEt) gave 1.5 g of 5-bromo-3-oxo-spiro[benzofuran-2(3H),4′-piperidin]-1′-carboxylic acid tert-butyl ester as a yellow crystalline solid.

Provenance & Evidence