Reacción #2183720

Ecuación de reacción

6-bromo-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one

MeOH Selectfluor

→

6-bromo-3-fluoro-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one

Rendimiento 10.0%

Condiciones de reacción

Tratamiento posterior

1. 1
   TemperaturaThe suspension was refluxed overnight
2. 2
   OtroThen the solvent was removed in vacuo
3. 3
   workup.ADDITIONCH2Cl2 was added to the resulting residue and insoluble material
4. 4
   Filtraciónfiltered off
5. 5
   LavadoThe filtrate was washed with H2O
6. 6
   Otrodried
7. 7
   Concentraciónconcentrate in vacuo
8. 8
   OtroThe crude product was purified by column chromatography

Procedimiento

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).

Fuente