Hydrochloric Acid → 2-(3-Fluorophenyl)-2-methylpyrrolidine

Participants

Reaction Conditions

Reaction Steps

A solution of 5-(3-fluorophenyl)-3,4-dihydro-2H-pyrrole (6.1 g, 37.4 mmol) in 100 mL THF was cooled to −78° C., and boron trifluoride diethyl etherate (9.47 mL, 74.8 mmol) was added drop-wise over 5 minutes. The resulting cloudy reaction mixture was stirred at −78° C. for 40 minutes. MeLi (1.6 M in diethyl ether, 46.7 mL, 74.8 mmol) was added drop-wise over 10 minutes. The mixture was stirred at −78° C. for another 2 hours, then warmed up to ambient temperature overnight. For workup, water and EtOAc were added to the reaction mixture, and the aqueous layer was acidified with HCl solution. After separating and discarding the organic layer, the aqueous layer was basified with NaOH (6 N, aq.) to pH=12 and extracted twice with EtOAc. The combined organic extracts was dried over Na2SO4 and concentrated to get a mixture of the desired product (2-(3-fluorophenyl)-2-methylpyrrolidine) and starting material (4.3 g, 1.3:1 of the desired product:starting material, 37% yield). The crude product was used in the next step without any further purification.

Provenance & Evidence