Trimethylsilyldiazomethane → 1-tert-Butyl 2-methyl (2R,4S)-4-hydroxypyrrolidine-1,2-dicarboxylate

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Reaction Steps

(Trimethylsilyl)diazomethane (2N solution in hexane, 2.9 ml) was added dropwise over 5 minutes to a stirred solution of (4S)-1-(tert-butoxycarbonyl)-4-hydroxy-D-proline (1.0 g) in DCM (20 ml) and methanol (5 ml) at room temperature until a permanent faint yellow colour persisted. The reaction mixture was concentrated in vacuo and purified by column chromatography, using 0-50% ethyl acetate in hexane as eluent, to give 1-tert-butyl 2-methyl (2R,4S)-4-hydroxypyrrolidine-1,2-dicarboxylate as a clear oil (1.03 g, 97%); NMR spectrum (CDCl3) 4.90-4.37 (m, 2H), 3.73 (s, 3H), 3.64 (dd, 1H), 3.53-3.43 (m, 1H), 2.34-2.27 (m, 1H), 2.12-1.97 (m, 2H), 1.46 (s, 3H), 1.41 (s, 6H).

Provenance & Evidence