Réaction #79367

Équation de réaction

tetrahydro-4H-pyran-4-one

magnesium

4-benzyloxy bromobenzene

→

4-(4-benzyloxyphenyl)tetrahydro-2H-pyran-4-ol

Rendement 55.1%

Solvants

THF

Conditions de réaction

Traitement

1. 1
   AutreIn a 100 ml round-bottomed flask was placed
2. 2
   Autreover 15 min
3. 3
   Températurewith occasional heating by a heat gun
4. 4
   workup.ADDITIONAfter the addition
5. 5
   Températureupon cooling in an ice-water bath
6. 6
   workup.STIRRINGAfter stirring for 30 min
7. 7
   Autrethe solvent was removed under reduced pressure
8. 8
   workup.ADDITIONdiluted with AcOEt and sat. NH4Cl aq. The organic phase
9. 9
   Autrewas separated
10. 10
    Concentrationconcentrated
11. 11
    Autrechromatographed on silica gel eluting with 40% AcOEt/hexanes

Mode opératoire

In a 100 ml round-bottomed flask was placed magnesium turnings (1.85 g, 76.1 mmol), which was stirred under vacuum without solvent overnight. To it were slowly added anhydrous THF 40 ml and 4-benzyloxy bromobenzene (10 g, 38 mmol) over 15 min with occasional heating by a heat gun to keep the Grignard reagent formation going. After the addition was complete, the resulting gray slurry was stirred for 1 hr at 60° C. To it was added tetrahydro-4H-pyran-4-one (3.5 ml, 38 mmol) upon cooling in an ice-water bath. After stirring for 30 min, the solvent was removed under reduced pressure and diluted with AcOEt and sat. NH4Cl aq. The organic phase was separated, concentrated, and chromatographed on silica gel eluting with 40% AcOEt/hexanes to give 4-(4-benzyloxyphenyl)tetrahydro-2H-pyran-4-ol 5.95 g (55%).

Source