Methyl iodide → Diisopropyl (2R,3S)-2-hydroxy-3-methylsuccinate

Temperatur

20 °C

To a cold (−78° C.) solution of diisopropyl-(S)-(−)-malate (4.72 mL, 22.9 mmol, 1 eq.) in anhydrous THF (8.50 mL) was added slowly a solution (1 M) of lithium bis(trimethylsilyl)amide (48.1 mL, 48.1 mmol, 2.10 eq.) in THF. The temperature was raised to 20° C. over 30 minutes, than lowered again to −78° C. Iodomethane (1.7 mL, 28 mmol, 1.20 eq.) was added and the mixture stirred at RT for 16 hours. The reaction mixture was then cooled to 0° C. and a saturated solution of NH4Cl was added. The resulting mixture was diluted with water, extracted three times with EtOAc. The combined organic phases were washed with brine, dried over MgSO4, filtered and evaporated under reduced pressure. The residue was then purified by chromatography (SiO2, 20/80 EtOAc/c-hex) to give the product (mixture of diatereoisomers) as a colourless oil (3.77 g, 71%).

1. customthan lowered again to −78° C
2. temperatureThe reaction mixture was then cooled to 0° C.
3. extractionextracted three times with EtOAc
4. washThe combined organic phases were washed with brine
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. customevaporated under reduced pressure
8. customThe residue was then purified by chromatography (SiO2, 20/80 EtOAc/c-hex)
9. customto give

ORD-Eintrag

ord-74e584a170694903a647c786b6e3f8b4

Quelldatensatz

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08247437B2