diethyl (3S,4S)-1-benzylpyrrolidine-3,4-dicarboxylate → (3R,4R)-1-tert-butyl 3,4-diethyl pyrrolidine-1,3,4-tricarboxylate

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Reaction Steps

A mixture of (3S*,4S*)-1-benzyl-pyrrolidine-3,4-dicarboxylic acid diethyl ester (82.8 g, 271.14 mmol), di-tert-butylcarbonate (88.76 g, 406.71 mmol) and Pd/C 10% (8 g) in EtOH (1.5 L) is stirred under hydrogen atmosphere. The crude material is filtered over a pad of Celite and concentrated. The crude material is purified by flash chromatography on silica gel (eluent: CH2Cl2/acetone 100:0 to 95:5). TLC, Rf (CH2Cl2/acetone 95:5)=0.51. MS (LC-MS): 216.2 [M+H-Boc]+.

Provenance & Evidence