反应详情

温度

-78 °C

A 1 L three-necked 24/40 round-bottom flask equipped with a mechanical stirrer, a 250 mL constant pressure addition funnel with a nitrogen inlet at the top, and a septum was flame dried, cooled and then charged with a solution of 29.07 g (0.17 mol) of p-bromotoluene in 100 mL of anhydrous tetrahydrofuran under a nitrogen atmosphere. The solution was stirred and cooled to -78° C. and 200 mL (0.34 mol) of a 1.7M solution of t-butyllithium in pentane was added via the addition funnel over 30 minutes. When the addition was complete, the cooling bath was removed and the reaction mixture was stirred for 30 minutes and allowed to warm to room temperature. The dropping funnel was next charged with 170 mL (0.17 mol) of a 1.0M solution of zinc chloride in diethylether which was added to the reaction mixture over a 10 minute period. A separate 1 L three-necked 24/40 round-bottom flask equipped with a mechanical stirrer, a nitrogen inlet and a septum, was flame dried, cooled and then charged with 4.04 g (6.0 mmol) of bis(triphenylphosphine)palladium(II) chloride and 50 mL of anhydrous tetrahydrofuran under a nitrogen atmosphere. The stirrer was started and 8.0 mL of a 1.5M solution (12 mmol) of diisobutylaluminum hydride in toluene was added to the suspension via syringe. The catalyst was stirred an additional 10 minutes at room temperature, and then a solution of 23.23 g (0.115 mol) of 1-bromo-2-nitrobenzene in 100 mL of anhydrous tetrahydrofuran was added. The suspension of the tolylzinc chloride was then transferred to the second flask via a wide diameter cannula. The reaction mixture was stirred an additional 45 minutes at room temperature, then most of the tetrahydrofuran was removed on a rotary evaporator. The resulting oil was partitioned between ethyl acetate and 1.0N hydrochloric acid. The organic layer was washed successively with water and brine, then dried (MgSO4), filtered and evaporated. The residual oil was purified on a silica gel flash chromatography column eluted with 10% ethyl acetate-hexane to afford after evaporation and drying in vacuo 15.43 g (63%) of the product as a viscous yellow oil:

1. customA 1 L three-necked 24/40 round-bottom flask equipped with a mechanical stirrer, a 250 mL constant pressure addition funnel with a nitrogen inlet at the top
2. temperaturea septum was flame
3. customdried
4. temperaturecooled
5. additionWhen the addition
6. customthe cooling bath was removed
7. stirringthe reaction mixture was stirred for 30 minutes
8. temperatureto warm to room temperature
9. additionThe dropping funnel was next charged with 170 mL (0.17 mol) of a 1.0M solution of zinc chloride in diethylether which
10. additionwas added to the reaction mixture over a 10 minute period
11. customA separate 1 L three-necked 24/40 round-bottom flask equipped with a mechanical stirrer, a nitrogen inlet
12. temperaturea septum, was flame
13. customdried
14. temperaturecooled
15. stirringThe catalyst was stirred an additional 10 minutes at room temperature
16. stirringThe reaction mixture was stirred an additional 45 minutes at room temperature
17. custommost of the tetrahydrofuran was removed on a rotary evaporator
18. customThe resulting oil was partitioned between ethyl acetate and 1.0N hydrochloric acid
19. washThe organic layer was washed successively with water and brine
20. dry with materialdried (MgSO4)
21. filtrationfiltered
22. customevaporated
23. customThe residual oil was purified on a silica gel flash chromatography column
24. washeluted with 10% ethyl acetate-hexane
25. customto afford
26. customafter evaporation
27. dry with materialdrying in vacuo 15.43 g (63%) of the product as a viscous yellow oil