反应详情

To a solution of (2S,4S)-1-(benzyloxycarbonyl)-4-methoxypyrrolidine-2-carboxylic acid (3.0 g, 0.01 mol) in methanol (40 mL0 and diethyl ether (20 mL) was added (trimethylsilyl)diazomethane (2.0 M solution in diethyl ether, 6.4 mL, 0.013 mol) dropwise under ice-bath. The reaction mixture was stirred at room temperature for 1 h. Concentration of the reaction mixture gave (2S,4S)-1-benzyl 2-methyl 4-methoxypyrrolidine-1,2-dicarboxylate 18B (3.2 g, 100%) as an oil which was used in the next step without purification. 1H NMR (CDCl3, 400 MHz) δ 7.27-7.36 (m, 5H), 5.04-5.19 (m, 2H), 4.39-4.50 (m, 1H), 3.91-3.94 (m, 1H), 3.53-3.72 (m, 5H), 3.24 (s, 3H), 2.21-2.35 (m, 2H).