6-Bromo-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-one → 6-Bromo-3-fluoro-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-one

Participants

Reaction Steps

To a solution of 6-bromo-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one (2 g, 6.8 mmol) in MeOH Selectfluor™ (2.5 g, 7.1 mmol) was added. The suspension was refluxed overnight. Then the solvent was removed in vacuo. CH2Cl2 was added to the resulting residue and insoluble material filtered off. The filtrate was washed with H2O, dried and concentrate in vacuo. The crude product was purified by column chromatography to give 6-bromo-3-fluoro-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one (220 mg, 10%). 1H-NMR (CDCl3): 1.72-2.21 (m, 4H), 3.44 (m, 1H), 3.63 (m, 1H), 3.73 (m, 1H), 3.92 (m, 1H), 4.91 (m, 1H), 6.94 (m, 1H), 7.56 (m, 1H), 7.90 (m, 1H).

Provenance & Evidence