반응 #70661

반응 방정식

tert-butyl lithium

acetone dry ice

THF

4-bromobenzocyclobutane

tert-Butyllithium

→

3-(4-bromobutyl)bicyclo[4.2.0]octa-1(6),2,4-triene

반응 조건

후처리

1. 1
   기타To an oven-dried three-neck round-bottom flask equipped with an additional funnel and thermometer under nitrogen
2. 2
   기타to the reaction
3. 3
   workup.ADDITIONthrough the addition
4. 4
   기타the reaction temperature below −65° C
5. 5
   기타the dry ice/acetone bath was removed
6. 6
   온도cooled down to −73° C. in dry ice/acetone bath
7. 7
   workup.ADDITION65.7 mL 1,4-dibromobutane was added drop-wise via syringe
8. 8
   기타stayed lower than −65° C
9. 9
   온도to slowly warm to room temperature overnight
10. 10
    기타The reaction was quenched by the addition of isopropanol (25 mL)
11. 11
    기타the solvent was removed by rotary evaporation
12. 12
    workup.ADDITIONEthyl acetate (500 mL) was added
13. 13
    추출extracted with DI water (1000 mL×2) and brine (200 mL×5)
14. 14
    건조The combined organic layer was dried over anhydrous magnesium sulfate
15. 15
    기타the solvent was removed by evaporation
16. 16
    기타was removed by vacuum
17. 17
    workup.DISTILLATIONdistilled at 90° C
18. 18
    여과Filtration through a Celite/silica gel plug
19. 19
    기타afforded 24.1 g NMR and GC-MS pure product

실험 절차

To an oven-dried three-neck round-bottom flask equipped with an additional funnel and thermometer under nitrogen, were added 500 mL anhydrous THF and 25.0 g 4-bromobenzocyclobutane. The reaction mixture was then cooled down to −73° C. in acetone/dry ice bath. 161 mL tert-Butyllithium (2M) was added drop by drop to the reaction through the addition, while keeping the reaction temperature below −65° C. After addition of tert-butyl lithium, the dry ice/acetone bath was removed and the reaction was allowed to warm up to −20° C., and then cooled down to −73° C. in dry ice/acetone bath. 65.7 mL 1,4-dibromobutane was added drop-wise via syringe, ensuring the reaction temperature stayed lower than −65° C. The reaction was allowed to slowly warm to room temperature overnight. The reaction was quenched by the addition of isopropanol (25 mL), and the solvent was removed by rotary evaporation. Ethyl acetate (500 mL) was added and then extracted with DI water (1000 mL×2) and brine (200 mL×5). The combined organic layer was dried over anhydrous magnesium sulfate, and the solvent was removed by evaporation. The excess starting material, 1,4-dibromobutane, was removed by vacuum distilled at 90° C. Filtration through a Celite/silica gel plug afforded 24.1 g NMR and GC-MS pure product.

출처