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

Participants

Reaction Conditions

Reaction Steps

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%).

Provenance & Evidence