Tert-butyl 3-oxopyrrolidine-1-carboxylate → tert-Butyl 3-methylidenepyrrolidine-1-carboxylate

Temperature

0 °C

To a suspension consisting of methyl triphenylphosphonium bromide (18 g, 51 mmol) and THF (200 mL) at 0° C. was added n-butyl lithium (1.6 M solution in hexanes, 32 mL). The resulting orange solution was stirred at 0° C. for 5 min, then a solution of 3-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (9.0 g, 48 mmol) in THF (40 mL) was added via cannula. The reaction mixture was stirred at 0° C. for 90 min, then warmed to rt and stirring was continued for 1 h. The reaction mixture was then cooled to 0° C., quenched with sat. NH4Cl, and extracted with Et2O. The organic layer was dried (MgSO4) and concentrated. The crude residue was suspended in hot hexanes and filtered. The filtrate was concentrated and purified (FCC) to give the title compound (4.4 g, 50%).

1. stirringThe reaction mixture was stirred at 0° C. for 90 min
2. temperaturewarmed to rt
3. stirringstirring
4. waitwas continued for 1 h
5. temperatureThe reaction mixture was then cooled to 0° C.
6. customquenched with sat. NH4Cl
7. extractionextracted with Et2O
8. dry with materialThe organic layer was dried (MgSO4)
9. concentrationconcentrated
10. filtrationfiltered
11. concentrationThe filtrate was concentrated
12. custompurified (FCC)

ORD record

ord-fb4cbec086e84fa892b67ba937c9784c

Source dataset

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08901111B2