反应详情

To a solution of (2S,4S)-1-tert-butyl 2-methyl 4-((difluoromethoxy)methyl)pyrrolidine-1,2-dicarboxylate (2.41 g, 7.79 mmol) in a mixture of THF (39 mL) and MeOH (15.6 mL) was added LiOH (2.5 M aqueous, 15.6 mL, 38.9 mmol). The resulting solution was stirred at room temperature for 1 h. Upon completion by TLC the reaction mixture was acidified with aqueous HCl (1N). The desired product was extracted with CH2Cl2 (3×). The combined organic layers were dried over Na2SO4 and concentrated to provide (2S,4S)-1-(tert-butoxycarbonyl)-4-((difluoromethoxy)methyl)pyrrolidine-2-carboxylic acid (2.4 g, 99%). MS (ESI) m/z 294.96 [M−H]−. 1H-NMR: 400 MHz, (acetone-d6) δ (mixture of rotamers): 6.50 (t, 1H), 4.36-4.17 (m, 1H), 3.93 (d, 2H), 3.77-3.67 (m, 1H), 3.63-3.59 (m, 1H), 3.26-3.12 (m, 1H), 2.72-2.41 (m, 2H), 1.89-1.73 (m, 2H), 1.41 (s, 9H).

1. extractionThe desired product was extracted with CH2Cl2 (3×)
2. dry with materialThe combined organic layers were dried over Na2SO4
3. concentrationconcentrated