Hexamethylphosphoramide → Ethyl 2-((2-methyl-1,3-dioxolan-2-yl)methyl)pentanoate

To a cooled (−78° C.) solution of lithium diisopropylamine (30 mL; 60 mmol; 2N in THF) in THF (8 mL) was added hexamethylphosphoramide (12 mL) and the solution was stirred for 30 min. A solution of ethyl 3-(2-methyl-1,3-dioxolan-2-yl)propanoate (9.4 g; 50 mmol), in THF (9 mL), was added over 30 min and stirring was continued for 1 h. Propyl iodide (6.84 mL; 70 mmol) was slowly added and the solution was allowed to warm to room temperature for 4 h. the reaction was quenched by adding a saturated aqueous solution of ammonium chloride. The two phases were separated and the aqueous layer was extracted with ethyl acetate (50 mL) and the combined organic layers were dried with sodium sulphatesulphate, filtered and concentrated under reduced pressure. The crude residue was purified by flash-chromatography on silica gel using a gradient of ethyl acetate (0-40%) in heptane to furnish 9.8 g (85%) of ethyl 2-((2-methyl-1,3-dioxolan-2-yl)methyl)pentanoate as an oil.

1. stirringstirring
2. waitwas continued for 1 h
3. customwas quenched
4. additionby adding a saturated aqueous solution of ammonium chloride
5. customThe two phases were separated
6. extractionthe aqueous layer was extracted with ethyl acetate (50 mL)
7. dry with materialthe combined organic layers were dried with sodium sulphatesulphate
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customThe crude residue was purified by flash-chromatography on silica gel using a gradient of ethyl acetate (0-40%) in heptane

ORD-Eintrag

ord-09a1289354ea4c0c82459690074912f1

Quelldatensatz

uspto-grants-2014_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08785638B2