Reaktionsgleichung
[O:1]1[CH:5]=[CH:4][CH:3]=[CH:2]1.Cl[CH:7](Cl)[C:8]([CH2:10]Cl)=[O:9]>CO.[Zn].[Pd]>[CH:5]12[O:1][CH:2]([CH:3]=[CH:4]1)[CH2:10][C:8](=[O:9])[CH2:7]2.[CH:5]12[O:1][CH:2]([CH2:3][CH2:4]1)[CH2:10][C:8](=[O:9])[CH2:7]2Komponenten
Edukt 2
Produkt 2
Reagenzien, Katalysatoren, Lösungsmittel 3
Versuchsvorschrift
8-Oxa-bicyclo[3.2.1]oct-6-en-3-one was synthesized by the known [4+3]cycloaddition of the commercially available furan and the oxyally generated from 1,1,3-trichloroacetone, followed by reduction with zinc (J. Org. Chem. 1999,64, 3398 and J. Am. Chem. Soc. 2001, 123, 5590). Internal double bond of the cycloadduct was reduced using Pd/C in MeOH to give 8-oxa-bicyclo[3.2.1]octan-3-one. The resulting ketone was subjected to Eadsworth-Horner-Emmons condition to yield the α,β-unsaturated ester. Catalytic hydrogenation of the conjugated ester gave rise to an inseparable mixture (˜1:1) of diasteromers with no diastereoselectivity. The mixture of diastereomers carried forward to the next two steps. These steps include reduction of esters with NaBH4/LiCl followed by treatment with TsCl in the presence of NEt3 to furnish the oxabicyclo[3.2.1]octaneethylmethylbenzensolfonate. 1H NMR (CDCl3): δ 7.81-7.78 (m, 2H), 7.37-7.34 (m, 2H), 4.35-4.28 (m, 2H), 4.07-4.02 (m, 2H), 2.46 (s, 3H), 2.07 (m, 1H), 1.95-1.87 (m, 2H), 1.82-1.76 (m, 1H), 1.68-1.63 (m, 2H), 1.55-1.50 (m, 2H), 1.43-1.28 (m, 2H), 1.10 (m, 1H).
Quellen und Nachweise
- ORD-Eintrag
- ord-41d7e8b64d524bea96b5b1a4a55961f5
- Quelldatensatz
- uspto-grants-2013_07
- Patentnummer
- US08476285B2
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