Reaktion #324746

Reaktionsgleichung

2,5-dibromo-1,3-dimethylbenzene

2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

K3PO4

→

title compound

4-(4-Bromo-3,5-dimethylphenyl)-3,6-dihydro-2H-pyran

Lösungsmittel

toluene

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigewater (1.2 mL) and purged for 10 minutes with argon
2. 2
   workup.ADDITION[1,1′-Bis(diphenylphosphino)-ferrocene]-dichloropalladium-(II) (100 mg) is added
3. 3
   Sonstigethe vial is sealed
4. 4
   TemperaturAfter cooling to room temperature the mixture
5. 5
   workup.ADDITIONis diluted with diethylether
6. 6
   Waschenwashed with saturated aqueous NH4Cl solution
7. 7
   TrocknenThe organic phase is dried (MgSO4)
8. 8
   Einengenconcentrated
9. 9
   SonstigeThe residue is chromatographed on silica gel (cyclohexane/ethyl acetate 99:1→60:40)

Vorschrift

In a microwave vial 2,5-dibromo-1,3-dimethylbenzene (800 mg), 2-(3,6-dihydro-2H-pyran-4-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (640 mg) and K3PO4 (1.3 g) are suspended in toluene (12 mL) and water (1.2 mL) and purged for 10 minutes with argon. [1,1′-Bis(diphenylphosphino)-ferrocene]-dichloropalladium-(II) (100 mg) is added, the vial is sealed and the mixture is stirred at 60° C. for 12 hours. After cooling to room temperature the mixture is diluted with diethylether and washed with saturated aqueous NH4Cl solution. The organic phase is dried (MgSO4) and concentrated. The residue is chromatographed on silica gel (cyclohexane/ethyl acetate 99:1→60:40) to give the title compound. Yield: 404 mg.

Quelle