反应详情

To a solution of N,N-diethyl-4-bromo-benzamide (128 mg, 0.5 mmol) (see structural formula at entry 3 of Table 1) and Cp2ZrCl2(207 mg, 0.7 mmol, 1.4 eq.) in THF (3 mL) at RT was rapidly added a 1 M tetrahydrofuran (THF) solution of LiAlH(Ot-Bu)3 (0.7 mL, 0.7 mmol, 1.4 eq.). After addition, thin layer chromatography (TLC) using EtOAc/Hexanes showed the substrate had been consumed completely. The reaction was quenched by distilled H2O immediately. Dilute acid (0.5 N HCl in distilled water) was added until the pH was less than 5. Then EtOAc was added (3×10 mL) and the mixture was extracted. Combined organic layers were washed with brine, dried over MgSO4 and concentrated via evaporation under reduced pressure. Initial purification of the crude product was performed by passing the solution through a filter of silica gel (silica gel 60, 230-400 mesh). Purity was then checked by TLC. If further purification was needed, it was performed by flash column chromatography (silica gel 60, 230-400 mesh) using EtOAc/hexanes as eluent. 4-Bromobenzaldehyde (89 mg, 96% yield) was obtained as a colorless solid. Its melting point was determined to be 55-56° C. (hexanes).

1. additionAfter addition, thin layer chromatography (TLC)
2. customhad been consumed completely
3. customThe reaction was quenched
4. distillationby distilled H2O immediately
5. additionDilute acid (0.5 N HCl in distilled water)
6. additionwas added until the pH was less than 5
7. additionThen EtOAc was added (3×10 mL)
8. extractionthe mixture was extracted
9. washCombined organic layers were washed with brine
10. dry with materialdried over MgSO4
11. concentrationconcentrated via evaporation under reduced pressure
12. customInitial purification of the crude product
13. filtrationa filter of silica gel (silica gel 60, 230-400 mesh)
14. customIf further purification