Réaction #11284

Équation de réaction

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

Rendement 72.8%

Solvants

THF

Conditions de réaction

Traitement

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

Mode opératoire

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.

Source