Reaktion #87127

Reaktionsgleichung

Water

benzyl 3,3-difluorocyclobutanecarboxylate

Meldrum's acid

EDCI

→

5-(3,3-difluorocyclobutanecarbonyl)-2,2-dimethyl-1,3-dioxane-4,6-dione

Ausbeute 76.3%

Lösungsmittel

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   FiltrationPd/C was filtered off
2. 2
   Einengenthe filtrate was concentrated
3. 3
   workup.DISSOLUTIONThe residue was dissolved in dichloromethane (200 mL)
4. 4
   Extraktionthe resulting mixture was extracted with dichloromethane (300 mL×3)
5. 5
   Trocknendried over anhydrous sodium sulfate
6. 6
   Einengenconcentrated
7. 7
   SonstigeThe residue was purified by flash column chromatography on silica gel (dichloromethane/methanol=100:1 to 20:1)

Vorschrift

A mixture of benzyl 3,3-difluorocyclobutanecarboxylate (28 g, 0.12 mol) and Pd/C (5 g) in methanol (150 mL) was hydrogenated for 2 h at ambient temperature. Pd/C was filtered off and the filtrate was concentrated. The residue was dissolved in dichloromethane (200 mL) and cooled to 0° C. DMAP (30.8 g, 0.250 mol), Meldrum's acid (19.6 g, 0.140 mol) and EDCI (26.9 g, 0.140 mol) were added successively. The reaction mixture was stirred overnight at ambient temperature. Water (200 mL) was added and the resulting mixture was extracted with dichloromethane (300 mL×3). The organic extracts were combined, dried over anhydrous sodium sulfate, and concentrated. The residue was purified by flash column chromatography on silica gel (dichloromethane/methanol=100:1 to 20:1) to afford 5-(3,3-difluorocyclobutanecarbonyl)-2,2-dimethyl-1,3-dioxane-4,6-dione (24 g, 74% yield).

Quelle