Benzyl chloroformate → 1-Benzyl 2,3-di-tert-butyl pyrazolidine-1,2,3-tricarboxylate

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Reaction Steps

Sat. aq. K2CO3 (210 mL) was added into a solution of benzyl chloroformate (12.0 ml, 84 mmol) and crude di-tert-butyl pyrazolidine-1,5-dicarboxylate (12.74 g, assumed 46.8 mmol) in acetonitrile (137 ml) at 0° C. The reaction was allowed to warm to room temperature and was stirred for 4.5 hrs. The aqueous phase was extracted with EtOAc (3×100 mL), and the organic layers were dried over Na2SO4. The solvents were removed in vacuo, and the crude product was purified by silica gel chromatography (CombiFlash, Column: 220 g; 0-35% ethyl acetate in hexane; 60 min) to provide the desired product 1-benzyl 2,3-di-tert-butyl pyrazolidine-1,2,3-tricarboxylate (14.15 g, 74% yield) as a white solid.

Provenance & Evidence