1,1-Dibromoethane → 1-(N,N-diethylamino)-2,5-dimethylborolane

HRID 236427

Reaktionsgleichung

Reaktionsgleichung von HRID 236427
BrC(Br)C.Br[CH:6]([CH2:8][CH2:9][CH:10](Br)[CH3:11])[CH3:7].[CH2:13]([N:15]([B:18](Cl)Cl)[CH2:16][CH3:17])[CH3:14]>C1COCC1.CCOCC>[CH2:13]([N:15]([B:18]1[CH:6]([CH3:7])[CH2:8][CH2:9][CH:10]1[CH3:11])[CH2:16][CH3:17])[CH3:14]

Komponenten

6

Edukt 3

HCID 112011,1-DibromoethaneHCID 912322,5-DibromohexaneHCID 5326278Boranamine, 1,1-dichloro-N,N-diethyl-

Produkt 1

HCID 139306611-(N,N-diethylamino)-2,5-dimethylborolaneAusbeute 63 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 3283Diethyl EtherLösungsmittelHCID 8028TetrahydrofuranLösungsmittel2×

Reaktionsbedingungen

Temperatur
20 °C

Versuchsvorschrift

Dibromoethane (3.0 mL, 0.035 mol) was added to a mechanically stirred suspension of Mg turnings (78 g, 3.21 mol) in THF (160 mL). After 30 min. most of the THF was removed via cannula and fresh THF (270 mL) was added. Then a solution of 2,5-dibromohexane (299 g, 1.24 mol) in THF (650 mL) was added at a rate that maintained the internal temperature at 30°-34° C. The resulting mixture was stirred overnight, filtered through glass wool and diluted with THF to a volume of 2 L. Hydrolysis of an aliquot and titration for total base showed the concentration of this solution to be 0.39M (63% yield, typically 60-65%). The Grignard solution was added to a cooled, magnetically stirred solution of N,N-diethylaminodichloroborane (124 g, 0.80 mol) in ether (1.0 L) at a rate that allowed maintenance of an internal temperature of -70° to -65° C. The resulting suspension was allowed to warm to 20° C. overnight. The solids were allowed to settle and the supernatant was removed via cannula. The solids were washed with pentane (four times) and the combined supernatants were concentrated by fractional distillation. The residue was vacuum transferred to a cold (dry ice-acetone) receiver by heating the residue to 120° C. at 0.1 torr. Distillation under reduced pressure gave the diethylaminoborolane 7 as a mixture of isomers (72.8 g, 0.44 mol) in 56% yield. On a small scale yields up to 70% were obtained.

Aufarbeitung

  1. customAfter 30 min. most of the THF was removed via cannula and fresh THF (270 mL)
  2. additionwas added
  3. temperaturethat maintained the internal temperature at 30°-34° C
  4. filtrationfiltered through glass wool
  5. additiondiluted with THF to a volume of 2 L
  6. customHydrolysis of an aliquot and titration for total base
  7. custommaintenance of an internal temperature of -70° to -65° C
  8. customthe supernatant was removed via cannula
  9. washThe solids were washed with pentane (four times)
  10. concentrationthe combined supernatants were concentrated by fractional distillation
  11. temperatureby heating the residue to 120° C. at 0.1 torr
  12. distillationDistillation under reduced pressure

Quellen und Nachweise

ORD-Eintrag
ord-fd0ecc78df2a449f9970d3f0b231612d
Quelldatensatz
uspto-grants-1987_02
Patentnummer
US04644075

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