Allyl bromide → Methyl 2,3,3-trimethylbutanoate

HRID 1955691

Reaktionsgleichung

Reaktionsgleichung von HRID 1955691
[CH:1]([NH:4][CH:5]([CH3:7])[CH3:6])([CH3:3])[CH3:2].C([Li:12])CCC.[CH3:13][CH:14]([C:19]([CH3:22])([CH3:21])[CH3:20])[C:15]([O:17][CH3:18])=[O:16].C=C1CC1.C(Br)C=C.CN(P(N(C)C)(N(C)C)=O)C>C1COCC1>[CH:1]([N-:4][CH:5]([CH3:7])[CH3:6])([CH3:3])[CH3:2].[Li+:12].[CH3:13][CH:14]([C:19]([CH3:22])([CH3:21])[CH3:20])[C:15]([O:17][CH3:18])=[O:16]

Komponenten

9

Edukt 6

HCID 7841Allyl bromideHCID 7912DiisopropylamineHCID 12679HexamethylphosphoramideHCID 80245MethylenecyclopropaneHCID 140630Methyl 2,3,3-trimethylbutanoateHCID 178418339Butyllithium

Produkt 2

HCID 140630Methyl 2,3,3-trimethylbutanoateHCID 2724682Lithium diisopropylamide

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 8028TetrahydrofuranLösungsmittel3×

Versuchsvorschrift

A solution of lithium diisopropylamide was prepared by treating diisopropylamine (40.91 g, 405 mmol) in dry THF (350 mL) with butyllithium in hexanes (2.5M, 154.4 mL, 386 mmol) at 0° C. for 15 min in a nitrogen atmosphere. Then a solution of methyl 2,3,3-trimethylbutyrate (38.88 g, 270 mmol) in THF (30 mL) was added slowly, and the mixture was stirred. Methyl 2,3,3-trimethylbutyrate was prepared as in Quast H, Meichsner G, Seiferling B (1986) "Photochemical formation of methylenecyclopropane analogs. XII. Synthesis of 3,5,5-trialkyl-3,5-dihydro-4H-1,2,3-triazol-4-ones" Liebigs. Ann. Chem., 1891-1899. After 45 min. of stirring, the temperature of the mixture was reduced to -78° C. and a solution of allyl bromide (51.30 g, 424 mmol) in THF (20 mL) and HMPA (40.3 mL, 232 mmol) was added over a period of 15 min. Stirring was continued for 2 h at -78° C. and the system was allowed to warm to room temperature (ca. 6 h). The reaction was quenched by addition of HCl (3N, 300 mL) at 0° C. The layers were separated and the aqueous phase was further extracted with ether (3×150 mL). The combined organic extract was washed sequentially with 100 mL portions of water, 5% Na2S2O3, saturated NaHCO3, water, and brine, and dried over MgSO4. The solvent was removed in vacuo to give 48.88 g of brown colored liquid, which upon two vacuum distillations, afforded olefinic ester (34.85 g, 70%) as a colorless liquid: bp 87°-89° C. (20 mmHg).

Aufarbeitung

  1. stirringAfter 45 min. of stirring
  2. customwas reduced to -78° C.
  3. stirringStirring
  4. customThe reaction was quenched by addition of HCl (3N, 300 mL) at 0° C
  5. customThe layers were separated
  6. extractionthe aqueous phase was further extracted with ether (3×150 mL)
  7. extractionThe combined organic extract
  8. washwas washed sequentially with 100 mL portions of water, 5% Na2S2O3, saturated NaHCO3, water, and brine
  9. dry with materialdried over MgSO4
  10. customThe solvent was removed in vacuo

Quellen und Nachweise

ORD-Eintrag
ord-b6fff69cdfea449c8996099cb6aabe5e
Quelldatensatz
uspto-grants-1998_07
Patentnummer
US05776959

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