Hydrochloric Acid → 1-Cbz-3-methylenepyrrolidine

Participants

Reaction Conditions

Reaction Steps

A 8.44 ml (77 mmol) portion of titanium tetrachloride was added dropwise to 350 ml of tetrahydrofuran solution containing 36.6 g (600 mmol) of zinc at 0° C., and the mixture was stirred for 60 minutes at the same temperature. To the reaction solution cooled at 0° C. was added dropwise 24.32 ml (350 mmol) of dibromomethane dissolved in 100 ml of tetrahydrofuran, followed by stirring at room temperature overnight. To the reaction solution was added dropwise tetrahydrofuran (100 ml) solution of 15.35 g (70 mmol) 1-benzyloxycarbonyl-3-pyrrolidone at room temperature, followed by 50 minutes of stirring at the same temperature. After completion of the reaction, the reaction solution was mixed with 500 ml of 1 N hydrochloric acid and extracted with ethyl acetate (500 ml×2), and the organic layer was washed with saturated brine (300 ml×1). After drying the organic layer over anhydrous sodium sulfate, the solvent was evaporated. The resulting residue was subjected to a silica gel column chromatography to yield 12.4 g (82%) of the title compound as an oily product from the eluate of n-hexane:ethyl acetate=2:1.

Provenance & Evidence