Expedient synthesis of a highly substituted tropolone via a 3-oxidopyrylium [5+2] cycloaddition reaction
作者:Jack E. Baldwin、Alexander V.W. Mayweg、Gareth J. Pritchard、Robert M. Adlington
DOI:10.1016/s0040-4039(03)00987-0
日期:2003.6
An expedient ten-step synthesis of a substituted tropolone is described. The synthesis involves a 3-oxidopyrylium [5+2] cycloaddition reaction with acrylonitrile as the key step, affording a highly functionalized [3.2.1]-bicycle 10 as a single regioisomer. The nitrile substituent of the reduced cycloadduct 12 permits efficient ether-bridge cleavage and tropolone 15 is obtained after a final bis-oxidation
描述了方便的十步合成取代的托酚酮。该合成涉及3-氧化吡啶鎓[5 + 2]环加成反应,其中丙烯腈为关键步骤,从而提供了高度功能化的[3.2.1]-双环10作为单个区域异构体。还原的环加合物12的腈取代基允许有效的醚桥裂解,并且在最终的双氧化过程之后获得了pol托酮15。乙酸吡喃糖环加成前体衍生自3-糠基-2-甲基酯。