Acetone → 7-fluoro-2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-4-one

Participants

Reaction Steps

1-(4-Fluoro-2-hydroxy-phenyl)-ethanone (5.0 g, 32.44 mmol), acetone (11.92 mL, 162.2 mmol) and pyrrolidine (2.7 mL, 32.44 mmol) were dissolved in 20 mL benzene, and the reaction mixture was refluxed for four hours. The reaction mixture was cooled to room temperature and partitioned between ethyl acetate and 1 N HCl. The organic layer was dried over MgSO4, and solvent was evaporated under reduced pressure. The resulting residue was chromatographed (15% ethyl acetate in hexanes eluting through silica) and solvent was removed to yield 3.33 g (17.16 mg, 53%) of 7-fluoro-2,2-dimethyl-chroman-4-one as an oil. MS: 195 (M+H)+.

Provenance & Evidence