Preparative Organic Chemistry
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ChemInform Abstract: Epimerization and Stereoselectivity in the Diels-Alder Reaction of Monosubstituted Dienophiles.
First published: May 2, 1989
Abstract
Diels-Alder reaction of trans-1,3-pentadiene (I) with acrolein (II) under various conditions yields predominantly the endo-cycloadducts (III).
ChemInform Abstract
Diels-Alder reaction of trans-1,3-pentadiene (I) with acrolein (II) under various conditions yields predominantly the endo-cycloadducts (III). The epimerization of (III) and (IV) in a GC column at various temperatures is also studied, a 84:16 ratio of (III) and (IV) is changed to a 75:25 ratio by raising the temperature from 60 to 160°C. The dienophiles (V) react with (I) to give the endo- (VI) and exo-adducts (VII). Treatment of a mixture of (VIa) and (VIb) and (VIIa) and (VIIb) with boron trifluoride etherate favours the exo-adducts (VII).
