Methyl chloroformate → 1-Ethyl 1-methyl 4,4-dimethoxycyclohexane-1,1-dicarboxylate

Temperatur

-78 °C

To a −78° C. solution of iPr2NEt (3.95 mL, 27.7 mmol) in THF (50 mL) was added n-BuLi (17.3 mL of a 1.6 M solution in hexanes; 27.7 mmol) was added. After 15 min, ethyl 4,4-dimethoxycyclohexane-carboxylate (4.0 g, 18.50 mmol) was added and the reaction mixture was stirred at −78° C. for 1 h. Methyl chloroformate (2.87 mL, 37.0 mmol) was added and the reaction mixture was warmed to rt. The reaction was quenched with saturated aqueous NH4Cl and extracted with EtOAc (100 mL). The organic layer was dried (Na2SO4) and concentrated in vacuo. The crude oil was chromatographed (SiO2; continuous gradient from 0 to 20% EtOAc:hexanes) to afford the title compound (4.7 g, 93% yield) as a clear oil. 1H NMR (500 MHz, CDCl3) δ 4.21 (q, J=7.1 Hz, 2H), 3.75 (s, 3H), 3.19 (s, 6H), 2.16-2.05 (m, 4H), 1.79-1.69 (m, 4H), 1.27 (t, J=7.1 Hz, 3H).

1. addition27.7 mmol) was added
2. temperaturethe reaction mixture was warmed to rt
3. customThe reaction was quenched with saturated aqueous NH4Cl
4. extractionextracted with EtOAc (100 mL)
5. dry with materialThe organic layer was dried (Na2SO4)
6. concentrationconcentrated in vacuo
7. customThe crude oil was chromatographed (SiO2; continuous gradient from 0 to 20% EtOAc:hexanes)

ORD-Eintrag

ord-c51c0c97070d4c2598db687da4866168

Quelldatensatz

uspto-grants-2015_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08962660B2