Citric Acid → (2S,3S)-3-heptyloxiranemethanol

Temperatur

0 °C

A suspension of 2.00 g of 4A powdered molecular sieves in 50 ml of dry CH2Cl2 was cooled to 0° C. under argon. To the cooled suspension was added 273 mg (1.00 mmole) of Ti(OiPr)4 and 314 mg (1.34 mmole) of L(+)diisopropyl tartrate via syringe. The mixture was stirred for 15 min and cooled to -20° C. A solution of tert-butylhydroperoxide in isooctane (3.8M, 7.57 ml, 28.8 mmole) was added slowly to the mixture and the catalyst was allowed to "age" for 30 min at -20° C. A solution of 3.00 g (19.2 mmole) of E-2-decen-1-ol in 10 ml of CH2Cl2 was dried over 3A molecular sieves for 15 min before being added to the mixture slowly, with stirring, at -20° C. The solution was then placed in the freezer (-30 ° C.) and allowed to stand for 24 H. The mixture was warmed to 0° C. and poured into a solution of 1.00 g of citric acid and 5.00 g of FeSO4 in 15 ml H2O. The organic layer was separated and the aqueous layer washed twice with 20 ml of CH2Cl2. The CH2Cl2 layers are combined, dried over MgSO4, filtered and evaporated to yield a sticky white solid. Recrystallization from Et2O: petroleum ether afforded 2.43 g of white solid, mp 50°-1° C. 1H NMR δ3.92 (ddd, 1, J=2, 6, 12 Hz), 3.63 (ddd, 1, J=4, 8, 12 Hz), 2.94 (m, 2), 1.73 (dd, 1, J=6, 7 Hz), 1.6-1.2 (m, 12), 0.88 (t, 3, J=7 Hz). Mass Spectra: M-31(-CH2O H)(0.5)148.1, M(100)69.1.

1. temperaturecooled to -20° C
2. waitthe catalyst was allowed to "age" for 30 min at -20° C
3. additionbefore being added to the mixture slowly
4. stirringwith stirring, at -20° C
5. customwas then placed in the freezer (-30 ° C.)
6. temperatureThe mixture was warmed to 0° C.
7. customThe organic layer was separated
8. washthe aqueous layer washed twice with 20 ml of CH2Cl2
9. dry with materialdried over MgSO4
10. filtrationfiltered
11. customevaporated
12. customto yield a sticky white solid
13. customRecrystallization from Et2O

ORD-Eintrag

ord-1793a6e5bc134526b5b59b0b403de57f

Quelldatensatz

uspto-grants-1993_03

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05190969