Water → Tert-butyl 4-(5-bromo-2-fluorobenzoyl)-4-hydroxypiperidine-1-carboxylate

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Reaction Steps

Pyridine tribromide (12.7 g, 39.6 mmol) and TBAB (850 mg, 2.64 mmol) were added to a stirred solution of 4-[2-(5-bromo-2-fluoro-phenyl)-[1,3]dithian-2-yl]-4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester (13 g, 26.42 mmol) and pyridine (2.07 ml, 39.63 mmol) in a mixture of DCM/water (5:1, 180 ml). After stirring for 24 h at RT, the solution was poured into water (150 ml) and the product was extracted with DCM. The combined organic layers were washed with water (400 ml), brine (400 ml), dried over Na2SO4, then filtered and evaporated. The crude product was purified by column chromatography (AcOEt/hexane:20/80) to give 9.5 g of 4-(5-bromo-2-fluoro-benzoyl)-4-hydroxy-piperidine-1-carboxylic acid tert-butyl ester as a yellow oil.

Provenance & Evidence