反应详情

温度

-78 °C

Phenyllithium (12.5 ml. of a 2.0M solution in 7:3 benzene-ethyl ether) is added to a dry-ice cooled, stirring solution of diethyl N-benzylidene-aminomethylphosphonate (6.073 g., 23.8 mMol) in dry tetrahydrofuran (130 ml.). After having been stirred for 30 minutes at -78°C. under a N2 atmosphere, the solution is treated dropwise over 25 minutes with a solution of trichloroethyl chloroformate (5.04 g., 23.8 mMol) in dry tetrahydrofuran (25 ml.). The resulting solution is stirred an additional 2 hours at -78°C., then allowed to warm to 3°C. over a period of 30 minutes. Evaporation of the solvent in vacuo yields a yellow foam which is partitioned between ethyl ether (150 ml.) and 0.5M pH3 phosphate buffer (50 ml.). The aqueous phase is separated and extracted with two additional portions of ether (25 ml.). The combined ethereal solution is washed with saturated brine (100 ml.), dried over MgSO4, and evaporated under reduced pressure to give a cloudy, yellow oil. Chromatography of the crude product on silica gel (200 g.) using 9:1 ethyl acetate-acetone as eluting solvent gives trichloroethyl N-benzylidene-α-amino-diethylphosphonoacetate as a pale yellow oil.

1. temperaturecooled
2. stirringThe resulting solution is stirred an additional 2 hours at -78°C.
3. temperatureto warm to 3°C. over a period of 30 minutes
4. customEvaporation of the solvent in vacuo
5. customyields a yellow foam which
6. customis partitioned between ethyl ether (150 ml.) and 0.5M pH3 phosphate buffer (50 ml.)
7. customThe aqueous phase is separated
8. extractionextracted with two additional portions of ether (25 ml.)
9. washThe combined ethereal solution is washed with saturated brine (100 ml.)
10. dry with materialdried over MgSO4
11. customevaporated under reduced pressure
12. customto give a cloudy, yellow oil
13. washas eluting solvent