反应详情

温度

-78 °C

3a, 7a-dihydroxy-octahydro-4,8-dioxa-2,6-diaza-s-indacene-2,6-dicarboxylic acid di-tert-butyl ester Dimethyl sulfoxide (279 μl, 3.94 mmol) was added dropwise to a stirred solution of oxalyl chloride (258 μl, 2.95 mmol) in THF (10 ml) at −78° C. After 10 min (3S,4S)-3,4-dihydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester (0.5 g, 2.46 mmol) [Nagel, Angew. Chem., 96, 425 (1984)] in THF (5 ml) was added. The mixture was stirred at −78° C. for 95 min, after which triethylamine (1.7 ml, 12.3 mmol) was added. Stirring was continued for a further 20 min, after which the mixture was allowed to warm to room temperature. Citric acid (5% solution) (20 ml) was added and the mixture extracted with ethyl acetate. The organic extracts were combined, dried (MgSO4), filtered, and concentrated in vacuo then purified by flash column chromatography on silica gel, eluting with 50-70% ethyl acetate in petroleum ether to give 3a, 7a-dihydroxy-octahydro-4,8-dioxa-2,6-diaza-s-indacene-2,6-dicarboxylic acid di-tert-butyl ester (195 mg, 20%); m/z (ES+) 425 (100%, [MNa]+).

1. stirringStirring
2. waitwas continued for a further 20 min
3. temperatureto warm to room temperature
4. extractionthe mixture extracted with ethyl acetate
5. dry with materialdried (MgSO4)
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customthen purified by flash column chromatography on silica gel
9. washeluting with 50-70% ethyl acetate in petroleum ether