Tetrahydrofuran → tert-Butyl 3-(fluoro(phenylsulfonyl)methylene)azetidine-1-carboxylate

Temperatur

-78 °C

To a mixture of fluoromethyl phenyl sulfone (0.50 g, 2.9 mmol) and phosphorochloridic acid, diethyl ester (0.415 mL, 2.87 mmol) in tetrahydrofuran (6 mL, 70 mmol) was added 1.000 M of lithium hexamethyldisilazide in tetrahydrofuran (6.2 mL, 6.2 mmol) dropwise at −78° C. After the mixture was stirred at −78° C. for 1 h, a solution of tert-butyl 3-oxoazetidine-1-carboxylate (0.378 g, 2.21 mmol) in tetrahydrofuran (1.3 mL, 16 mmol) was added. The reaction was allowed to warm to ambient temperature and stirred for 2 h at rt. The reaction was poured into an ice-cold mixture of EtOAc and sat. ammonium chloride. The organic layer was separated and the aq. layer was extracted with EtOAc. The combined organic layers were washed with brine, and dried over sodium sulfate. The solvent was removed under reduced pressure and the resulting residue was purified on silica gel, eluting with 0 to 50% EtOAc in hexane, to give the desired product (560 mg, 77.5%). LCMS calculated for C15H18FNO4SNa(M+Na)+: m/z=350.1. Found (M+Na) 350.3.

1. temperatureto warm to ambient temperature
2. stirringstirred for 2 h at rt
3. customThe organic layer was separated
4. extractionthe aq. layer was extracted with EtOAc
5. washThe combined organic layers were washed with brine
6. dry with materialdried over sodium sulfate
7. customThe solvent was removed under reduced pressure
8. customthe resulting residue was purified on silica gel
9. washeluting with 0 to 50% EtOAc in hexane

ORD-Eintrag

ord-441ce3b4ae454e68a06ff71232fb289e

Quelldatensatz

uspto-grants-2013_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08420629B2