Pyrrolidine → tert-Butyl 6-bromo-4-oxospiro[chroman-2,4'-piperidine]-1'-carboxylate

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Reaction Steps

A mixture of 2-hydroxy-5-bromoacetophenone (10.75 g, 50 mmol), N—BOC-4-piperidone (9.96 g, 50 mmol) and pyrrolidine (2.09 ml, 25 mmol) in MeOH (80 ml) was heated to reflux for 11 h. The solvent was removed under vacuum and the crude mixture was purified by column chromatography (eluent: hexane/AcOEt 90:10 to 80:20) to give 6-bromo-4-oxo-spiro[chromane-2,4′-piperidine]-1′-carboxylic acid tert-butyl ester (18.55 g) as a yellow solid.

Provenance & Evidence