Reaktion #76223

Reaktionsgleichung

AD-mix-α

water tert-butyl alcohol

2-(benzyloxy)-1-(3-butenyl)-3-methoxybenzene

water tert-butyl alcohol

→

(2S)-4-[2-(benzyloxy)-3-methoxyphenyl]-1,2-butanediol

Ausbeute 92.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeThe reaction mixture is quenched by the addition of sodium sulfite
2. 2
   workup.ADDITIONThe reaction mixture is diluted with water (500 mL) and ethyl acetate (500 mL)
3. 3
   SonstigeThe aqueous phase is separated
4. 4
   Extraktionextracted with ethyl acetate (2×200 mL)
5. 5
   WaschenThe combined organic extracts are washed with aqueous sodium chloride (400 mL)
6. 6
   Trocknendried (magnesium sulfate)
7. 7
   Sonstigethe solvent is removed in vacuo
8. 8
   Sonstigeto give a crude oil
9. 9
   SonstigePurification by flash column chromatography (silica, ethyl acetate:hexanes 4:1)

Vorschrift

To a suspension of AD-mix-α (63.28 g) in water:tert-butyl alcohol (1:1, 300 mL) cooled to 0° C. is slowly added via an addition funnel to a solution of 2-(benzyloxy)-1-(3-butenyl)-3-methoxybenzene (12.13 g, 45.2 mmol) in water:tert-butyl alcohol (1:1, 300 mL). The reaction mixture is allowed to stir at room temperature for 12 h. The reaction mixture is quenched by the addition of sodium sulfite. The reaction mixture is diluted with water (500 mL) and ethyl acetate (500 mL). The aqueous phase is separated and extracted with ethyl acetate (2×200 mL). The combined organic extracts are washed with aqueous sodium chloride (400 mL), dried (magnesium sulfate) and the solvent is removed in vacuo to give a crude oil. Purification by flash column chromatography (silica, ethyl acetate:hexanes 4:1) provides 12.57 g (92%, 40% ee) of (2S)-4-[2-(benzyloxy)-3-methoxyphenyl]-1,2-butanediol as a colorless oil. [α]D25=−3.04 (c 10.2 in methanol, 40% ee); Rf=0.72 (silica, ethyl acetate:hexanes 4:1); Anal. Calcd. for C18H22O4.0.1H2O: C, 71.08; H, 7.36. Found: C, 70.95; H, 7.33.

Quelle