Diisopropylamine → HCID 68312814, Verbindung

Temperatur

-30 °C

n-Butyllithium (2.5M in hexanes, 1.01 mL, 2.54 mmol) was added to a solution of diisopropylamine (0.376 mL, 2.658 mmol) in THF (10 mL) at −30° C. under a nitrogen atmosphere. Stirring at −30° C. was continued for 45 min, and the reaction mixture was cooled to −78° C. A solution of 4-benzyloxy-2-methylbutyric acid benzyl ester (0.721 g, 2.416 mmol) in THF (8 mL) was added over 5 min and stirring at −78° C. was continued for 1 h. A solution of carbon tetrabromide (CBr4) (1.20 g, 3.62 mmol) in THF (2 mL) was added and the mixture was slowly warmed to 0° C. over 3.5 h. The reaction mixture was quenched by addition of a saturated solution aqueous of NH4Cl and then extracted with EtOAc (×2). The combined organic layers were washed with water, followed by brine, then dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si-PCC, gradient 3-18% EtOAc in cyclohexane) affording 4-benzyloxy-2-bromo-2-methylbutyric acid benzyl ester (0.434 g), used in the following step without further purification.

1. temperaturethe reaction mixture was cooled to −78° C
2. stirringstirring at −78° C.
3. waitwas continued for 1 h
4. temperaturethe mixture was slowly warmed to 0° C. over 3.5 h
5. customThe reaction mixture was quenched by addition of a saturated solution aqueous of NH4Cl
6. extractionextracted with EtOAc (×2)
7. washThe combined organic layers were washed with water
8. dry with materialdried (Na2SO4)
9. concentrationconcentrated in vacuo
10. customThe resulting residue was purified by column chromatography (Si-PCC, gradient 3-18% EtOAc in cyclohexane)

ORD-Eintrag

ord-e88b496332174cdc8d29b1521ab8a906

Quelldatensatz

uspto-grants-2015_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09090628B2