Reaktion #657297

Reaktionsgleichung

HCl

DCM

n-BuLi

pinanediol

B(OEt)3

→

Intermediate 1

Ausbeute 65.7%

(3aS,4S,6S)-2-(dichloromethyl)-3a,5,5-trimethylhexahydro-4,6-methano-1,3,2-benzodioxaborole

Ausbeute 65.7%

Lösungsmittel

THF

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGthe mixture was stirred for 1 h at −45° C. to −30° C
2. 2
   Temperaturwhile maintaining the temperature below −20° C.
3. 3
   workup.STIRRINGthe resulting mixture was stirred at −20° C. for 4 h
4. 4
   SonstigeThe organic layer was separated
5. 5
   Extraktionthe water layer was extracted with diethyl ether (100 mL×2)
6. 6
   TrocknenThe combined organic layers were dried over anhydrous Na2SO4
7. 7
   Einengenconcentrated
8. 8
   Sonstigeto give an intermediate
9. 9
   workup.STIRRINGThe reaction mixture was stirred overnight at room temperature
10. 10
    Einengenconcentrated in vacuo
11. 11
    SonstigeThe residue was purified by column chromatography (petroleum ether:EtOAc 10:1 to 1:1)

Vorschrift

To a solution of DCM (80 mL, 1.2 mol) in THF (800 mL) at −80° C. to −90° C. was added n-BuLi (2.5 M in hexane, 480 mL, 1.2 mol) under N2, and the reaction mixture was stirred for 1.5 h below −80° C. B(OEt)3 (200 mL, 1.2 mol) was added in one portion and the mixture was stirred for 1 h at −45° C. to −30° C. Aqueous HCl (5 M, 240 mL, 1.2 mol) was then added dropwise while maintaining the temperature below −20° C. and the resulting mixture was stirred at −20° C. for 4 h. The organic layer was separated, and the water layer was extracted with diethyl ether (100 mL×2). The combined organic layers were dried over anhydrous Na2SO4 and concentrated to give an intermediate. The intermediate was re-dissolved in diethyl ether (800 mL) and pinanediol (188 g, 1.1 mol) was added to the solution. The reaction mixture was stirred overnight at room temperature and then concentrated in vacuo. The residue was purified by column chromatography (petroleum ether:EtOAc 10:1 to 1:1) to afford Intermediate 1 (190 g, 60% yield).

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