4-Bromo-2-fluorobenzaldehyde → 4-Bromo-1-ethenyl-2-fluorobenzene

Temperature

-78 °C

To a suspension of methyltriphenylphosphonium bromide (1.1 eq) in tetrahydrofuran (0.13M) at −78° C., was added n-butyllithium (2.5M in hexanes, 1.1 eq) dropwise over 20 min. The reaction mixture was stirred at −78° C. for 15 min, warm to 0° C., stirred for 15 min and cooled back to −78° C. A solution of 4-bromo-2-fluoro-benzaldehyde (1 eq) in 100 mL THF was added dropwise over 30 min. Final mixture was allowed to warm slowly to rt and stirred for 1 h. The resulting mixture was quenched with a saturated NH4Cl solution and diluted with 2 volume of hexane. The organic extract was washed with brine, dried over MgSO4, filtered and concentrated. The residue was diluted with Hexane/EtOAc (9:1) and filtered on a pad of Silica gel. The fractions were combined and concentrated to afford the desired material

1. temperaturewarm to 0° C.
2. stirringstirred for 15 min
3. temperaturecooled back to −78° C
4. temperatureto warm slowly to rt
5. stirringstirred for 1 h
6. customThe resulting mixture was quenched with a saturated NH4Cl solution
7. additiondiluted with 2 volume of hexane
8. extractionThe organic extract
9. washwas washed with brine
10. dry with materialdried over MgSO4
11. filtrationfiltered
12. concentrationconcentrated
13. additionThe residue was diluted with Hexane/EtOAc (9:1)
14. filtrationfiltered on a pad of Silica gel
15. concentrationconcentrated

ORD record

ord-a7712998b4cc4b088e6205f79c49d39e

Source dataset

uspto-grants-2008_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07342024B2