反应详情

A solution of carbon tetrabromide (2.204 gm, 6.65 mmol) in CH2Cl2 (8 ml) was added over a 12 minute period to a cold (-12° C.) solution of 4-(4-fluorophenyl)-2-(1-methylethyl)-6-phenyl-3-pyridinecarboxaldehyde (1.415 gm, 4.43 mmol) (the preparation of which is described in Example 1) and triphenylphosphine (3.488 gm, 13.3 mmol) in CH2Cl2 (25 ml). After the addition was complete, the cooling bath was removed and the mixture was stirred for 20 minutes. The solution was quenched with saturated NaHCO3 and extracted 3× with CH2Cl2. The combined organic layers were washed with saturated NaHCO3, dried (Na2SO4), filtered and stripped to give a yellow oil. The oil was chromatographed (flash, Merck SiO2, 40% CH2Cl2 in hexane) to give 3-(2,2-dibromoethenyl)-4-(4-fluorophenyl)-2-(1-methylethyl)-6-phenylpyridine as a colorless foam (2.152 gm, 100%).

1. customthe preparation of which
2. additionAfter the addition
3. customthe cooling bath was removed
4. customThe solution was quenched with saturated NaHCO3
5. extractionextracted 3× with CH2Cl2
6. washThe combined organic layers were washed with saturated NaHCO3
7. dry with materialdried (Na2SO4)
8. filtrationfiltered
9. customto give a yellow oil
10. customThe oil was chromatographed (flash, Merck SiO2, 40% CH2Cl2 in hexane)