Reacción #3011

Ecuación de reacción

hydrobromic acid

water

phenylmagnesium bromide

phenyl sulfoxide

→

triphenylsulfonium bromide

Disolventes

benzene

ether

dichloromethane

benzene

Condiciones de reacción

Tratamiento posterior

1. 1
   OtroTo a 3-necked 1 L round bottom flask equipped with a still head
2. 2
   Otrothe diethyl ether removed under vacuo
3. 3
   Temperaturaby gently heating
4. 4
   workup.ADDITIONAdditional benzene (150 ml) was added
5. 5
   Temperaturaa gentle reflux under nitrogen
6. 6
   workup.ADDITIONOnce the addition
7. 7
   Temperaturathe reaction mixture was heated at
8. 8
   Temperaturaa gentle reflux for 3 hours
9. 9
   TemperaturaThe reaction mixture was cooled (ice bath temperature)
10. 10
    OtroAfter separation of the layers
11. 11
    Extracciónthe organic layer extracted
12. 12
    Extracciónextracted with dichloromethane (200 ml)
13. 13
    Secadodried (MgSO4 )
14. 14
    Concentraciónconcentrated in vacuo
15. 15
    Otroto give the crude product as an off-white solid (14.50 g)
16. 16
    workup.ADDITIONadded
17. 17
    Otroto precipitate the salt
18. 18
    TemperaturaThe suspension was cooled in an ice bath for 1 hour
19. 19
    Otroto collecting the salt
20. 20
    Lavadowashing with ether

Procedimiento

To a 3-necked 1 L round bottom flask equipped with a still head was added phenylmagnesium bromide (3 M in diethyl ether, 142 ml, 0.426 mol) followed by dry benzene (150 ml). The flask was connected to a water aspirator and the diethyl ether removed under vacuo by gently heating. Additional benzene (150 ml) was added and the solution brought to a gentle reflux under nitrogen. A solution of phenyl sulfoxide (17.23 g, 85.2 mmol) in benzene (100 ml) was added dropwise over 1.5 hours. Once the addition was complete, the reaction mixture was heated at a gentle reflux for 3 hours. The reaction mixture was cooled (ice bath temperature) while adding a solution of hydrobromic acid (25%, 200 ml). The resulting biphasic mixture was stirred at room temperature overnight. After separation of the layers, the organic layer extracted were combined and extracted with dichloromethane (200 ml), dried (MgSO4 ) and concentrated in vacuo to give the crude product as an off-white solid (14.50 g). The solid was taken up in the minimum mount of warm dichloromethane (100 ml) and four times the volume of ether added to precipitate the salt. The suspension was cooled in an ice bath for 1 hour prior to collecting the salt and washing with ether. In this way, triphenylsulfonium bromide was isolated as a white solid (14.40 g, 49%).

Fuente