Domino intramolecular enyne metathesis/cross metathesis approach to the xanthanolides. Enantioselective synthesis of (+)-8-epi-xanthatin
作者:David A. Kummer、Jehrod B. Brenneman、Stephen F. Martin
DOI:10.1016/j.tet.2006.05.019
日期:2006.12
palladium-catalyzed carbonylation reaction to form acrylate 34. Compound 34 was then subjected to a deprotection/lactonization sequence to furnish enyne 21, which underwent a domino enyne ring-closing metathesis/cross metathesis process to form a seven-membered carbocycle and (E)-conjugated dienone, thereby completing the synthesis of 1. This domino ruthenium-catalyzed metathesis reaction thus serves as an efficient
从市售酯24开始,在14个步骤中实现了(+)-8-表-黄嘌呤素(1)的第一全合成,其在六个步骤中被转化为醛23。23的对映选择性醛醇缩合反应得到30,将其在四个步骤中转化为三氟甲磺酸酯22,为钯催化的羰基化反应形成丙烯酸酯34奠定了基础。然后对化合物34进行脱保护/内酯化序列以提供烯炔21,进行了多米诺烯环闭合复分解/交叉复分解过程,形成一个七元碳环和(E)共轭二烯酮,从而完成了1的合成。因此,这种多米诺骨牌钌催化的复分解反应是构建黄嘌呤内酯和其他倍半萜内酯核心的有效方法。