Reaktion #70661

Reaktionsgleichung

tert-butyl lithium

acetone dry ice

THF

4-bromobenzocyclobutane

tert-Butyllithium

→

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

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeTo an oven-dried three-neck round-bottom flask equipped with an additional funnel and thermometer under nitrogen
2. 2
   Sonstigeto the reaction
3. 3
   workup.ADDITIONthrough the addition
4. 4
   Sonstigethe reaction temperature below −65° C
5. 5
   Sonstigethe dry ice/acetone bath was removed
6. 6
   Temperaturcooled 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
   Sonstigestayed lower than −65° C
9. 9
   Temperaturto slowly warm to room temperature overnight
10. 10
    SonstigeThe reaction was quenched by the addition of isopropanol (25 mL)
11. 11
    Sonstigethe solvent was removed by rotary evaporation
12. 12
    workup.ADDITIONEthyl acetate (500 mL) was added
13. 13
    Extraktionextracted with DI water (1000 mL×2) and brine (200 mL×5)
14. 14
    TrocknenThe combined organic layer was dried over anhydrous magnesium sulfate
15. 15
    Sonstigethe solvent was removed by evaporation
16. 16
    Sonstigewas removed by vacuum
17. 17
    workup.DISTILLATIONdistilled at 90° C
18. 18
    FiltrationFiltration through a Celite/silica gel plug
19. 19
    Sonstigeafforded 24.1 g NMR and GC-MS pure product

Vorschrift

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.

Quelle