Reaktion #157935

Reaktionsgleichung

pinacolone

lithium diisopropylamide

hexane

pivalaldehyde

→

β-hydroxy ketone

Ausbeute 95.0%

5-Hydroxy-2,2,6,6,-tetramethyheptan-3-one

Ausbeute 95.0%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITthe reaction continued for another 12 hrs at room temperature
2. 2
   SonstigeThe reaction was quenched
3. 3
   workup.ADDITIONby adding 10 mL of water
4. 4
   SonstigeApproximately 80% THF was removed
5. 5
   workup.ADDITIONthe mixture was then poured into saturated aqueous solution of NH4Cl
6. 6
   ExtraktionThe aqueous layer was extracted twice with diethyl ether (200 mL)
7. 7
   Waschenthe organic layer was washed with plenty of water
8. 8
   TrocknenThe organic layer was then dried over MgSO4
9. 9
   Einengenconcentrated

Vorschrift

To a solution of pinacolone (10 g, 100 mmol, 1), in anhydrous THF (500 mL), at −78° C. a 2.0 M solution of lithium diisopropylamide (LDA) in hexane (60 mL, 120 mmol) over a period of 30 min. The reaction was stirred at −78° C. for another 30 min. To the resulting white suspension pivalaldehyde (10.9 mL, 100 mmol) was added drop-wise via syringe and the reaction continued for another 12 hrs at room temperature. The reaction was quenched by adding 10 mL of water. Approximately 80% THF was removed and the mixture was then poured into saturated aqueous solution of NH4Cl. The aqueous layer was extracted twice with diethyl ether (200 mL) and the organic layer was washed with plenty of water. The organic layer was then dried over MgSO4 and concentrated to give a crude yellow solid of β-hydroxy ketone (17.2 g, 95%, (2)). The crude product was recrystallized from hexane to give pure white solid with a yield of 81%.

Quelle