Tetrahydrofuran → 3-(4-Bromobutyl)bicyclo[4.2.0]octa-1(6),2,4-triene

Temperature

-20 °C

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.

1. customTo an oven-dried three-neck round-bottom flask equipped with an additional funnel and thermometer under nitrogen
2. customto the reaction
3. additionthrough the addition
4. customthe reaction temperature below −65° C
5. customthe dry ice/acetone bath was removed
6. temperaturecooled down to −73° C. in dry ice/acetone bath
7. addition65.7 mL 1,4-dibromobutane was added drop-wise via syringe
8. customstayed lower than −65° C
9. temperatureto slowly warm to room temperature overnight
10. customThe reaction was quenched by the addition of isopropanol (25 mL)
11. customthe solvent was removed by rotary evaporation
12. additionEthyl acetate (500 mL) was added
13. extractionextracted with DI water (1000 mL×2) and brine (200 mL×5)
14. dry with materialThe combined organic layer was dried over anhydrous magnesium sulfate
15. customthe solvent was removed by evaporation
16. customwas removed by vacuum
17. distillationdistilled at 90° C
18. filtrationFiltration through a Celite/silica gel plug
19. customafforded 24.1 g NMR and GC-MS pure product

ORD record

ord-da38e7ce48d74587a0de3f30a168f572

Source dataset

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08535974B2