Reacción #11284

Ecuación de reacción

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

Rendimiento 72.8%

Disolventes

THF

Condiciones de reacción

Tratamiento posterior

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

Procedimiento

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.

Fuente