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

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Reaction Steps

To a solution of crude (2S,4R)-4-hydroxy-2-methoxycarbonyl-1-p-nitrobenzyloxycarbonylpyrrolidine (86.1 g) in dichloromethane (1 liter) under ice cooling are added triethylamine (52 ml) and then methanesulfonyl chloride (21.6 ml), and the mixture is stirred for 25 minutes. The reaction mixture is acidified with diluted hydrochloric acid and stirred. The organic layer is taken, washed with aqueous sodium hydrogen carbonate and water, dried over sodium sulfate, and concentrated in vacuo to give (2S,4R)-4-methanesulfonyloxy-2-methoxycarbonyl-1-p-nitrobenzyloxycarbonylpyrrolidine (2: 90.0 g) as an organge oil. This product can be used in the next step without further purification. IR ν (CHCl3) cm-1 : 1741, 1703, 1602. 1HNMR δ (CDCl3) ppm: 2.22 to 2.82(2H, m), 3.07(3H, s), 3.67, 3.78(3H, 2s), 3.75 to 4.03(2H, m), 4.55(1H, t, J=7.8 Hz), 5.08 to 5.39(3H, m), 7.43 to 7.58(2H, m), 8.23(2H, d, J= 8.6 Hz).

Provenance & Evidence