Hydrochloric Acid → O1-benzyl O2-methyl 4-methylenepyrrolidine-1,2-dicarboxylate

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Reaction Steps

4-Methylene-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester 601 (10.0 g, 44 mmol) was dissolved in MeOH (75 mL) at room temperature and HCl (4M in dioxane, 75 mL) was added. Stirring at room temperature was continued for 4 hours. All volatiles were removed in vacuo and a beige solid was obtained. The crude material was suspended in methylene chloride (100 mL) and N-Methyl morpholine (13.3 g, 132 mmol) was added. The mixture was cooled to 0° C. and benzyl chloroformate (8.26 g, 48.4 mmol) was added while stirring. After 30 minutes, the reaction was warmed to room temperature and the solution was washed with water and aqueous HCl (1 M). The solution was dried over sodium sulfate. Filtration and evaporation of solvents gave crude product, which was purified by silica gel chromatography (eluent:EtOAc/hexanes) to yield compound 602 (10.2 g). LCMS-ESI+: calc'd for C15H17NO4: 275.3 (M+). Found: 276.4 (M+H+).

Provenance & Evidence