反应详情

温度

-78 °C

Tert-butyl (2R)-2-(2,2-dibromovinyl)pyrrolidine-1-carboxylate (Intermediate XXXVIII, 8.1 g, 22.8 mmol) was dissolved in dry THF (200 mL) and cooled to −78° C. Then added sec-butyllithium 1.4M in cyclohexane (32.6 mL, 45.6 mmol) over 30 minutes and continued mixing an additional 30 minutes before quenching with 20% ammonium chloride solution (200 mL). The mixture was warmed to rt and diluted with ethyl ether (200 mL). The organic phase was separated, washed with brine, dried in vacuo and purified on a silica gel column using a 100% to 99:1 gradient of methylene chloride to methanol as mobile phase to yield pure tert-buty (2R)-2-ethynylpyrrolidine-1-carboxylate. LC-MS m/z (minus t-butyl+1)=220. 1H NMR (CD3OD, 400 Mhz) 4.44 ppm (s, 1H), 3.44-3.37 (m, 1H), 3.34-3.25 (m, 1H), 2.61 (s, 1H), 2.08-1.85 (m, 4H), 1.47 (s, 9H).

1. additioncontinued mixing an additional 30 minutes
2. custombefore quenching with 20% ammonium chloride solution (200 mL)
3. temperatureThe mixture was warmed to rt
4. additiondiluted with ethyl ether (200 mL)
5. customThe organic phase was separated
6. washwashed with brine
7. customdried in vacuo
8. custompurified on a silica gel column