A Novel Synthesis of 2-Alkoxy-3-hydroxytropones and 2,7-Dihydroxytropones from Dialkoxy-8-oxabicyclo[3.2.1]oct-6-en-3-ones
作者:Hartmut Zinser、Sonja Henkel、Baldur Föhlisch
DOI:10.1002/ejoc.200300600
日期:2004.3
undergo cleavage of the ether bridge on heating with KOH in methanol, thus providing 2-alkoxy-3-hydroxytropones 20, which can be dealkylated to give the 2,7-dihydroxytropones (7-hydroxytropolones) 29. The lithium enolate generated from the α-oxo acetal 15a can be exo-alkylated with methyl iodide. Michael addition with 2-nitro-1-butene followed by a Nef reaction furnishes the bicyclic dioxo acetal 5. Treatment