Tetrahydrofuran → rac-3,4-dihydro-2,5,7,8-tetramethyl-2-(2-propenyl)-6-(phenylmethoxy)-2H-1-benzopyran

HRID 580370Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 580370
[CH2:1]([Mg]Cl)[CH:2]=C.Cl[C:7]1([CH3:28])[CH2:12][CH2:11][C:10]2[C:13]([CH3:27])=[C:14]([O:19][CH2:20][C:21]3[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=3)[C:15]([CH3:18])=[C:16]([CH3:17])[C:9]=2[O:8]1.O1CCC[CH2:30]1>CCOCC>[C:21]1([CH2:20][O:19][C:14]2[C:15]([CH3:18])=[C:16]([CH3:17])[C:9]3[O:8][C:7]([CH2:28][CH:1]=[CH2:2])([CH3:30])[CH2:12][CH2:11][C:10]=3[C:13]=2[CH3:27])[CH:22]=[CH:23][CH:24]=[CH:25][CH:26]=1

Komponenten

5

Edukt 3

HCID 8028TetrahydrofuranHCID 10246109rac-2-chloro-3,4-dihydro-2,5,7,8-tetramethyl-6-(phenylmethoxy)-2H-1-benzopyranHCID 178418473HCID 178418473, Verbindung

Produkt 1

HCID 14210609rac-3,4-dihydro-2,5,7,8-tetramethyl-2-(2-propenyl)-6-(phenylmethoxy)-2H-1-benzopyranAusbeute 57,2 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 3283Diethyl EtherLösungsmittel

Versuchsvorschrift

To 12 mL (24 mmol) of 2M allylmagnesium chloride in tetrahydrofuran, cooled in an ice bath, was added, with stirring, a solution of 4.95 g (14.98 mmol) of rac-2-chloro-3,4-dihydro-2,5,7,8-tetramethyl-6-(phenylmethoxy)-2H-1-benzopyran in 60 mL of anhydrous ether. The reaction mixture was stirred at 0° C. for 6 hr then worked up by being poured into cold, saturated NH4Cl solution and ether extraction. The product (5.4 g of a pale-yellow oil) was dissolved in 40 mL of methanol and 10 mL of ether containing 10 mg of p-toluenesulfonic acid monohydrate. The solution was stirred at room temperature for 21 hr then concentrated in vacuo. The residue was chromatographed on 75 g of silica gel. Elution with 40:1 parts by volume hexane-ether gave 2.88 g (57.2% yield) of rac-3,4-dihydro-6-(phenylmethoxy)-2-(2-propenyl)-2,5,7,8-tetramethyl-2H-1-benzopyran as a colorless oil.

Aufarbeitung

  1. additionwas added
  2. stirringThe reaction mixture was stirred at 0° C. for 6 hr
  3. additionby being poured into cold,
  4. extractionsaturated NH4Cl solution and ether extraction
  5. dissolutionThe product (5.4 g of a pale-yellow oil) was dissolved in 40 mL of methanol
  6. stirringThe solution was stirred at room temperature for 21 hr
  7. concentrationthen concentrated in vacuo
  8. customThe residue was chromatographed on 75 g of silica gel
  9. washElution with 40:1 parts by volume hexane-ether

Quellen und Nachweise

ORD-Eintrag
ord-ce0532aab284498684e815f112dfe423
Quelldatensatz
uspto-grants-1988_06
Patentnummer
US04752646

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