反应详情

温度

2.5 °C

Add a solution of trifluoroacetic acid (2.66 g, 23.3 mmol) in dichloromethane (11.7 mL) dropwise over 5 minutes to a stirred solution of diethyl zinc 1M in heptanes (23.3 mL, 23.3 mmol) in dichloromethane (11.7 mL) cooled to 0-5° C. under nitrogen (exothermic reaction). After 10 minutes, add a solution of diiodomethane (6.25 g, 23.3 mmol) in dichloromethane (11.7 mL). After 10 minutes, add a solution of diethyl (1S,2S,5R,6S)-2-(9H-fluoren-9-ylmethoxycarbonylamino)-4-methylene-bicyclo[3.1.0]hexane-2,6-dicarboxylate (3.70 g, 7.8 mmol) in dichloromethane (11.7 mL). After 2 hours at 0° C., allow to warm to room temperature and stir for 16 hours. Quench the reaction mixture with cold 0.5M hydrochloric acid (50 mL) and dichloromethane (20 mL) and stir vigorously. Separate the dichloromethane layer via a hydrophobic frit and then evaporate to a pale yellow oil. Purify by flash chromatography eluting with ethyl acetate:iso-hexane (10:90 to 20:80) to give a colorless oil (3.49 g). Repurify by flash chromatography eluting with ethyl acetate:iso-hexane (20:80) taking the centre cut fractions to give a colorless foam of title compound (2.12 g, 56%). MS (m/z): 490 (M+1). A second lot of product from the less pure fractions is obtained by repeated chromatography (363 mg, additional 9%).

1. waitAfter 10 minutes
2. waitAfter 2 hours at 0° C.
3. temperatureto warm to room temperature
4. customQuench the reaction mixture with cold 0.5M hydrochloric acid (50 mL) and dichloromethane (20 mL)
5. stirringstir vigorously
6. customSeparate the dichloromethane layer via a hydrophobic frit
7. customevaporate to a pale yellow oil
8. customPurify by flash chromatography
9. washeluting with ethyl acetate:iso-hexane (10:90 to 20:80)