Intramolecular Diels-Alder reactions of furans with a merely strain-activated tetrasubstituted alkene: Bicyclopropylidene
作者:Thomas Heiner、Sergei I. Kozhushkov、Mathias Noltemeyer、Thomas Haumann、Roland Boese、Armin de Meijere
DOI:10.1016/0040-4020(96)00720-x
日期:1996.9
Bicyclopropylidene derivatives 1, 6, 8 with furan moieties attached on tethers of various length and nature all undergo clean intramolecular Diels-Alder reactions with complete endo-diastereoselectivities when heated to 70 - 130 degrees C, under 10 kbar pressure. The reaction rates are at]east as high or higher than those of analogously tethered methylenecyclopropane-furan derivatives 15, 17, 20, in spite of the fact that the reactive double bond in bicyclopropylidene is tetrasubstituted and not activated by any electron withdrawing group. Copyright (C) 1996 Elsevier Science Ltd