Triethylamine → (2S,4R)-2-Methyl 1-(4-nitrobenzyl) 4-((methylsulfonyl)oxy)pyrrolidine-1,2-dicarboxylate

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Reaction Steps

To a solution of (2S,4R)-1-p-nitrobenzyloxycarbonyl-4-hydroxypyrrolidine-2-carboxylic acid methyl ester (59.44 g: 0.183 mole) in dichloromethane (150 ml) stirring at -20° C., triethylamine (30.5 ml: 1.2 eq.) and methanesulfonyl chloride (17 ml: 1 eq.) are added. The mixture is stirred at the same temperature for 35 minutes. To the mixture is added ice water and ethyl acetate. The organic layer is taken, washed with water, dried over magnesium sulfate, and concentrated in vacuo to give (2S,4R)-1-p-nitrobenzyloxycarbonyl-4-methanesulfonyloxypyrrolidine-2-carboxylic acid methyl ester (74.05 g). Yield: Quantitative. NMR δ(CDCl3) ppm: 2.20 to 2.42(m, 1H), 2.55 to 2.85(m, 1H), 3.07(s, 3H), 3.67(s, 1.5H), 3.78(s, 1.5H), 3.80 to 4.05(m, 2H), 4.53(t, J=7 Hz, 1H), 5.06 to 5.40(m, 3H), 7.47(d, J=9 Hz, 1H), 7.51(d, J=9 Hz, 1H), 8.23(d, J=9 Hz, 2H). IR ν (CHCl3) cm-1 : 1748, 1712, 1608.

Provenance & Evidence