Synthesis of Stereoisomers of <i>Artemisia</i> and <i>Chrysanthemum</i> Bis(acetylenic) Enol Ether Spiroacetals
作者:Boshen Wu、George C. Feast、Amber L. Thompson、Jeremy Robertson
DOI:10.1021/jo301810d
日期:2012.12.7
An 11-step synthesis is described of two diastereomeric candidates for a bis(acetylenic) enolether spiroacetal isolated from Chrysanthemum boreale. Key steps in the synthetic route include spiroacetal lactone alkylidenation and subseqent modified Cadiot–Chodkiewicz cross-coupling to install the bis(acetylenic) enolether functionality. From NMR comparisons, neither of the candidates, whose structures