Triethyl phosphonoacetate → Tert-butyl-3-(2-ethoxy-2-oxoethylidene)pyrrolidine-1-carboxylate

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Reaction Conditions

Reaction Steps

A flask was charged with NaH (50 g, 1.25 mol, 60% in mineral oil) and tetrahydrofuran (2,500 ml) and cooled to 0° C. A solution of ethyl 2-(diethoxyphosphoryl)acetate (260 g, 1.16 mol) in tetrahydrofuran F (200 ml) was added dropwise. The resulting solution was allowed stir for 1 h at 0° C. Then a solution of tert-butyl 3-oxopyrrolidine-1-carboxylate (215 g, 1.16 mol) in tetrahydrofuran (300 ml) was added dropwise. The resulting solution was allowed to stir for 0.5 hours at 0° C. The reaction mixture was quenched by the addition of 1,000 ml of saturated aqueous ammonium chloride. The resulting mixture was extracted with ethyl acetate (3×2,000 ml) and the combined organic layers were dried over sodium sulfate, filtered and concentrated. The residue was purified by column chromatography on silica gel (ethyl acetate/petroleum ether gradient) to afford tert-butyl-3-(2-ethoxy-2-oxoethylidene)pyrrolidine-1-carboxylate as colorless oil.

Provenance & Evidence