反应详情

To a 320 ml anhydrous THF solution of ethyl 7-benzyloxychromane-2-carboxyate 14.6 g (46.6 mmol) were added hexamethylphosphoramide (10.5 ml, 60.4 mmol). Upon cooling in a dry ice-acetone bath, sodium bis(trimethylsilyl)amide (1.0M/THF) (60.5 ml, 60.5 mmol) was added via syringe over 15 min period. The resulting orange solution was stirred at that temperature for 30 min before iodoethane (18.6 ml , 233 mmol) was added via syringe. The reaction was slowly warmed to rt and stirred overnight. The solvent was removed under reduced pressure, and the residue was diluted with AcOEt and aqueous NU4Cl (NH4Cl 7.2 g/200 ml water). The organic layer was separated, and the aqueous layer was extracted with AcOEt twice. The combined organic layers were dried over anhydrous Na2SO4, filtered, concentrated, and chromatographed on silica gel eluting with 7.5% EtOAc/hexanes to give the title compound 15.2 g (96%).

1. temperatureUpon cooling in a dry ice-acetone bath
2. additionwas added via syringe
3. customThe solvent was removed under reduced pressure
4. additionthe residue was diluted with AcOEt and aqueous NU4Cl (NH4Cl 7.2 g/200 ml water)
5. customThe organic layer was separated
6. extractionthe aqueous layer was extracted with AcOEt twice
7. dry with materialThe combined organic layers were dried over anhydrous Na2SO4
8. filtrationfiltered
9. concentrationconcentrated
10. customchromatographed on silica gel eluting with 7.5% EtOAc/hexanes