Diisopropylethylamine → (2R,3S)-2-(3-Chloro-2-fluoro-benzylcarbamoyl)-3-fluoro-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of (2R,3S)-3-fluoro-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester (120 mg, 0.514 mmol) in CH2Cl2 (5 mL) were added successively 3-chloro-2-fluorobenzylamine (0.065 mL, 0.514 mmol), HBTU (293 mg, 0.772 mmol) and DIPEA (0.18 mL, 1.03 mmol), and stirring was continued at RT for 20 h. The reaction mixture was then diluted with CH2Cl2, and the organics were washed with 0.1N aqueous HCl (2×), aqueous NaHCO3 (2×) and brine (1×), dried (Phase separator) and concentrated in vacuo. The residue was purified by flash column chromatography on silica gel (EtOAc/c-hexane gradient 1:4 to 1:3) to afford the title compound as a white foam. TLC Rf (EtOAc/c-hexane 1:1)=0.62; MS (LC/MS): 397 [M+Na]+, 319 [MH−tBu]+, 275 [MH−Boc]+; tR (HPLC conditions b): 4.72 min.

Provenance & Evidence