反应详情

To a solution of 2-(3,3-dimethylbutylamino)-cyclopent-1-enecarboxylic acid ethyl ester (5.59 g, 23.4 mmol) in acetic acid (70 mL) was added a 8.0 M solution of borane in pyridine (3.2 mL, 25.6 mmol) at 25° C. After stirring for 15 min, the reaction mixture was concentrated in vacuo. The crude material was triturated with 1.0 M aqueous hydrochloric acid solution (25 mL) and stirred for 0.5 h (until the gas evolution ceased). The mixture was extracted with ethyl acetate (3×50 mL) and the combined organic layers were dried over anhydrous magnesium sulfate and concentrated in vacuo. The crude material was purified by flash column chromatography (Teledyne Isco RediSep Flash Column; 0-10% methanol in dichloromethane) to afford cis-2-(3,3-dimethylbutylamino)-cyclopentanecarboxylic acid ethyl ester as a yellowish oil (0.40 g, 1.7 mmol, 7%) and trans-2-(3,3-dimethylbutylamino)-cyclopentanecarboxylic acid ethyl ester and an off-white solid (2.37 g, 9.8 mmol, 42%). cis-2-(3,3-Dimethylbutylamino)-cyclopentanecarboxylic acid ethyl ester: 1H NMR (400 MHz, CDCl3) δ 0.91 (9H, s), 1.28 (3H, t, J=7.0 Hz), 1.35-1.50 (2H, m), 1.56-1.73 (2H, m), 1.80-2.03 (4H, m), 2.60-2.75 (2H, m), 2.98-3.02 (1H, m), 3.35 (1H, q, J=7.4 Hz), 4.15 (2H, q, J=6.9 Hz), 6.38 (1H, s). trans-2-(3,3-Dimethylbutylamino)-cyclopentanecarboxylic acid ethyl ester: 1H NMR (400 MHz, CDCl3) δ 0.94 (9H, s), 1.29 (3H, t, J=7.0 Hz), 1.66-2.01 (6H, m), 2.11-2.27 (2H, m), 2.86 (2H, t, J=8.6 Hz), 3.10 (1H, q, J=7.8 Hz), 3.68 (1H, q, J=7.0 Hz), 4.18 (2H, q, J=7.0 Hz). LC-MS (ESI) calcd for C14H27NO2 241.20, found 242.4 [M+H+].

1. concentrationthe reaction mixture was concentrated in vacuo
2. customThe crude material was triturated with 1.0 M aqueous hydrochloric acid solution (25 mL)
3. stirringstirred for 0.5 h (until the gas evolution
4. extractionThe mixture was extracted with ethyl acetate (3×50 mL)
5. dry with materialthe combined organic layers were dried over anhydrous magnesium sulfate
6. concentrationconcentrated in vacuo
7. customThe crude material was purified by flash column chromatography (Teledyne Isco RediSep Flash Column; 0-10% methanol in dichloromethane)