Hydrochloric Acid → HCID 15327237、化合物

反応式

[CH3:1]/[C:2](=[CH:8]\[C:9](=[O:11])[CH3:10])/[C:3]([O:5][CH2:6][CH3:7])=[O:4].[BH4-].[Na+].Cl>CO>[OH:11][CH:9]([CH3:10])/[CH:8]=[C:2](\[CH3:1])/[C:3]([O:5][CH2:6][CH3:7])=[O:4]

参加物

反応条件

温度: 0 °C

実験手順

28 (ethyl (2E)-2-methyl-4-oxopent-2-enoate) (HPLC: ˜84 area %, 16.73 g, 90 mmol) is dissolved in MeOH (500 ml) and cooled to 0° C. To the resulting solution is added NaBH4 (1.04 g, 27.5 mmol) in portions over 30 min. After 3 hours additional stirring at 0° C., the pH is adjusted to 5 with 2 M HCl (12 ml). The reaction mixture is concentrated under reduced pressure at room temperature. H2O (100 ml) is added. After acidification with 2 M HCl to pH 1, extraction with tBuOMe (1 and 0.5 l) follows. The organic phases are washed with H2O (100 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 (AcOiPr:heptane fraction 20:80 to 40:60) and yields 29 (rac-Ethyl (2E)-4-hydroxy-2-methylpent-2-enoate) (11.26 g, 79%) as a yellowish oil.