Reaktion #11284

Reaktionsgleichung

2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

n-Butyllithium

acetone dry ice

4-bromo-N,N-diphenylaniline

→

N,N-diphenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline

Ausbeute 72.8%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.WAITwas continued at −78° C. for an hour
2. 2
   workup.WAITat −50° C. for an hour
3. 3
   TemperaturThe temperature was maintained at −78° C. for three hours
4. 4
   SonstigeThe cooling bath was removed
5. 5
   workup.WAITthe reaction left
6. 6
   Temperaturto warm to room temperature
7. 7
   workup.ADDITIONThe reaction mixture was poured into saturated ammonium acetate
8. 8
   Extraktionextracted with ether
9. 9
   TrocknenThe ether layer was dried over magnesium sulfate
10. 10
    Einengenconcentrated
11. 11
    Sonstigeto give a viscous oil
12. 12
    SonstigePurification
13. 13
    Temperaturby column chromatography (silica gel eluting with hexane:toluene mixtures of increasing gradient from 100% hexane to 40% hexane)

Vorschrift

n-Butyllithium was added dropwise via syringe to a −78° C. (acetone-dry ice cooling bath) solution of 4-bromo-N,N-diphenylaniline (24 g, 0.074 mole) in 175 ml dry THF. Stirring was continued at −78° C. for an hour and then at −50° C. for an hour. The mixture was cooled to −78° C. and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (17.22 g, 0.0925 mole) added via syringe in one portion. The temperature was maintained at −78° C. for three hours. The cooling bath was removed and the reaction left to warm to room temperature while standing for 12 hours. The reaction mixture was poured into saturated ammonium acetate and extracted with ether. The ether layer was dried over magnesium sulfate and concentrated to give a viscous oil. Purification by column chromatography (silica gel eluting with hexane:toluene mixtures of increasing gradient from 100% hexane to 40% hexane) gave N,N-diphenyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline as an oil (19.9 g, 72.8% yield), which slowly crystallized to a solid on standing.

Quelle