反应详情

To a solution of 3,5-dibromofluorobenzene in diethyl ether (100 cm3) at −78° C. was added n-butyl lithium (2.5 M, 8 cm3, 20 mmol) dropwise. After 30 min. the mixture was treated with DMF (20 cm3) in diethyl ether (10 cm3) and stirring was continued at −78° C. After 30 min. the mixture was quenched with dilute HCl aq., separated and the aqueous layer was extracted with EtOAc. The combined organic layers were combined, washed with water, brine, dried (MgSO4) and evaporated to give 3-fluoro-5-bromobenzaldehyde (4.0 g, 19.7 mmol, 100%) as an oil: 1H NMR (CDCl3) δ inter alia 7.50–7.53 (m, 2H), 7.82 (s, 1H) and 9.93 (m, 1H); MS (EI) m/z 202, 204 [M+].

1. customwas continued at −78° C
2. customAfter 30 min. the mixture was quenched with dilute HCl aq.
3. customseparated
4. extractionthe aqueous layer was extracted with EtOAc
5. washwashed with water, brine
6. dry with materialdried (MgSO4)
7. customevaporated