2-Pentynoic acid, 4-hydroxy-, ethyl ester → HCID 9989379, Verbindung
Reaktionsgleichung
[OH:1][CH:2]([CH3:10])[C:3]#[C:4][C:5]([O:7][CH2:8][CH3:9])=[O:6]>C1COCC1>[OH:1][CH:2]([CH3:10])/[CH:3]=[CH:4]/[C:5]([O:7][CH2:8][CH3:9])=[O:6]Komponenten
3
Edukt 1
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Reaktionsbedingungen
- Temperatur
- -70 °C
Versuchsvorschrift
NaAlH2[O(CH2)2OMe]2 (68.6% m/m, 82.2 g, 0.270 mol) is dissolved in THF (750 ml) and cooled to −70° C. 20 (rac-Ethyl 4-hydroxypent-2-inoate) (crude, HPLC: ˜90 area %, 21.33 g, 0.135 mol) in THF (500 ml) is added dropwise over 1.25 h at ≦−65°. After stirring for 2 hours at ≦−68° C. the reaction mixture is quenched with 2 M HCl (540 ml). Then water (250 ml) is added and the mixture is extracted with tBuOMe (1.5 and 1 l). The organic phases are washed with saturated NaHCO3 (250 ml) and brine (2×100 ml) successively. The combined organic phases are dried with Na2SO4 and evaporated under reduced pressure at 40° C. The residue is purified by flash chromatography (AcOEt:heptane fraction 20:80 to 40:60) and yields 21 (rac-Ethyl (2E)-4-hydroxypent-2-enoate) (15.56 g, 80%) as a yellow oil.