Hexamethylphosphoramide → Ethyl 4-oxooxane-3-carboxylate

Temperature

0 °C

Lithium diisopropylamide (1.14 mol/l solution in n-hexane/tetrahydrofuran, 2.5 ml) was added dropwise to a solution of tetrahydro-4H-pyran-4-one (260 mg) in tetrahydrofuran (13 ml) at −78° C., and the mixture was stirred for one hour while warming to 0° C. The reaction solution was cooled to −78° C. again, hexamethylphosphoric triamide (452 μl) was added and subsequently ethyl cyanoformate (280 μl) was added at the same temperature. The mixture was stirred over one hour while warming to 0° C. The reaction solution was separated by adding distilled water and ethyl acetate. The resulting organic layer was washed with brine and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure. The resulting residue was purified by silica gel column chromatography (developed with ethyl acetate-hexane) to give the title compound (210 mg).

1. temperatureThe reaction solution was cooled to −78° C. again
2. stirringThe mixture was stirred over one hour
3. temperaturewhile warming to 0° C
4. customThe reaction solution was separated
5. additionby adding
6. distillationdistilled water and ethyl acetate
7. washThe resulting organic layer was washed with brine
8. dry with materialdried over anhydrous sodium sulfate
9. customThe solvent was evaporated under reduced pressure
10. customThe resulting residue was purified by silica gel column chromatography (developed with ethyl acetate-hexane)

ORD record

ord-eab9fdb63ad947379333b412332b1b0e

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08436012B2