(±)-epi-Costunolide has been synthesized through a seven-step procedure starting from (E,E)-farnesol. The key step includes an intramolecular allylation of an aldehyde through a chromium(II)-mediated Nozaki–Hiyama–Kishi reaction, in which more than one equivalent of CrCl2 has been recognized as the most effective reagent to promote the conversion. An anti-inflammatory screen showed that epi-costunolide
(±) -外延-Costunolide已通过从(起始七步方法合成ë,ê)法呢醇。关键步骤包括通过铬 (II) 介导的 Nozaki-Hiyama-Kishi 反应使醛分子内烯丙基化,其中超过一当量的 CrCl 2被认为是促进转化的最有效试剂。抗炎筛选显示表木香内酯是 B 淋巴细胞增殖的中度抑制剂。
Substituent effects in the transannular cyclizations of germacranes. Synthesis of 6-epi-costunolide and five natural steiractinolides
作者:Redouan Azarken、Francisco M. Guerra、F. Javier Moreno-Dorado、Zacarías D. Jorge、Guillermo M. Massanet
DOI:10.1016/j.tet.2008.09.017
日期:2008.11
The occurrence and orientation of substituents in the 10-membered ring characteristic of germacranes is determinant in the stereochemical outcome of the acid-promotedtransannularcyclization of these metabolites. An explanation of the synthesis of eudesmanolides and guaianolides produced by the Umbelliferae family of plants is advanced. The syntheses of the natural products 6-epi-costunolide and five