Methanol → (3S,5S)-5-(3-Chloro-2-fluoro-benzylcarbamoyl)-pyrrolidine-1,3-dicarboxylic acid 1-tert-butyl ester 3-methyl ester

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Reaction Steps

Chlorotrimethylsilane (5.66 mL, 44.8 mmol) was added dropwise to dry MeOH (7.6 mL) at 0° C. followed by a solution of (2S,4S)-2-(3-chloro-2-fluoro-benzylcarbamoyl)-4-cyano-pyrrolidine-1-carboxylic acid tert-butyl ester (900 mg, 2.36 mmol) in dry CH2Cl2 (6.7 mL) and the resulting mixture was stirred at RT for 5 h. The mixture was cooled to 0° C., quenched with a saturated aqueous solution of NaHCO3 and extracted with CH2Cl2 (×3). To the organic extracts was added di-tert-butyl dicarbonate (514 mg, 2.36 mmol) at RT and the resulting solution was stirred overnight. The reaction mixture was concentrated in vacuo and the crude material purified by flash column chromatography (c-hexane to c-hexane/EtOAc 1:1) to give the expected compound. tR (HPLC conditions a): 3.50 min.

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