反应详情

To a solution of 3.80 g (23.4 mmol) 2,6-diethyl-benzaldehyde and 12.3 g (47 mmol) triphenylphosphine in 100 ml dry dichloromethane cooled to −20° C. was added drop-wise a solution of 9.32 g (28.1 mmol) tetrabromomethane in 70 ml dichloromethane. The reaction temperature was kept below 5° C. After the addition the reaction mixture was kept at −10° C. for 5 minutes and then for 30 minutes at ambient temperature. The reaction mixture was poured onto water, extracted with ethyl acetate, the combined extracts washed with brine, dried over Na2SO4, filtered and evaporated. The residue was purified by flash-chromatography on silica gel with a heptane/ethyl acetate gradient as eluent: 4.50 g 2-(2,2-dibromo-vinyl)-1,3-diethyl-benzene as colourless liquid: MS (EI): 319.9 and 318.0 and 316.0 (M+.), 239.1 and 237.1 ((M-Br)+.), 158.2 ((M-Br2)+., 100%).

1. customwas kept below 5° C
2. additionAfter the addition the reaction mixture
3. waitfor 30 minutes at ambient temperature
4. additionThe reaction mixture was poured onto water
5. extractionextracted with ethyl acetate
6. washthe combined extracts washed with brine
7. dry with materialdried over Na2SO4
8. filtrationfiltered
9. customevaporated
10. customThe residue was purified by flash-chromatography on silica gel with a heptane/ethyl acetate gradient as eluent