Reacción #570467

Ecuación de reacción

1,2-dibromoethane

hydrochloric acid

2-bromobenzaldehyde

1,2-dibromoethane

1,2-dibromoethane

magnesium

4-iodobenzotrifluoride

→

oil

Rendimiento 136.3%

4'-Trifluoromethyl-2-biphenylcarbaldehyde

Rendimiento 136.3%

Disolventes

THF

THF

THF

THF

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added dropwise
2. 2
   Temperaturato maintain gentle reflux
3. 3
   TemperaturaThe mixture was then refluxed an additional 20 minutes
4. 4
   Otrodecanted into an addition funnel
5. 5
   Otroattached to a second reaction flask
6. 6
   Temperaturathe mixture refluxed for 11/2 hr
7. 7
   Otrothe THF evaporated on the rotary evaporator
8. 8
   ExtracciónThe residue was extracted with diethyl ether
9. 9
   ExtracciónThe ether extract
10. 10
    Lavadowas washed with 3N hydrochloric acid (20 mL) water (4×25 mL), and saturated sodium chloride solution (10 mL)
11. 11
    SecadoThe ether solution was then dried (MgSO4)
12. 12
    workup.ADDITIONtreated with charcoal
13. 13
    Filtraciónfiltered
14. 14
    Otroevaporated

Procedimiento

To magnesium turnings (1.23 g, 50.7 mmol) in a dry flask under nitrogen was added anhydrous tetrahydrofuran (THF, 10 mL). The mixture was mechanically stirred while a solution of 1,2-dibromoethane (1.22 g, 6.5 mmol) in THF (10 mL) was added dropwise. Upon completion, a solution of the dimethyl acetal of 2-bromobenzaldehyde (3.00 g, 13.0 mmol) and 1,2-dibromoethane (2.44 g, 13.0 mmol) in THF (10 ml) was added at a rate to maintain gentle reflux. Upon completing, a second solution of 1,2-dibromoethane (1.22 g, 6.5 mmol) in THF (10 mL) was added dropwise. The mixture was then refluxed an additional 20 minutes and decanted into an addition funnel attached to a second reaction flask containing a solution of 4-iodobenzotrifluoride (2.72 g, 10.0 mmol) and iodo(4-trifluoromethyl)bis(triphenylphosphine)palladium (II) (0.21 g, 0.9 mmol) in refluxing THF (20 mL). The Grignard reagent was added dropwise and the mixture refluxed for 11/2 hr. After cooling to room temperature, 3N hydrochloric acid was added (30 mL) and the THF evaporated on the rotary evaporator. The residue was extracted with diethyl ether. The ether extract was washed with 3N hydrochloric acid (20 mL) water (4×25 mL), and saturated sodium chloride solution (10 mL). The ether solution was then dried (MgSO4), treated with charcoal, filtered and evaporated to give a dark yellow oil (3.41 g). This was chromatographed on the Waters Prep 500 HPLC using a 1:1 mixture of methylene chloride and hexane. The product was isolated after evaporation of solvent as a light yellow oil (2.41 g, 96.4%). 'H NMR (CDCl3): 7.6 (m, 7, Ar--H), 8.0 (m, 1, 3-H), 9.9 (s, 1, CHO).

Fuente