Studies on the synthesis of the indole alkaloids ngouniensine and epingouniensine
作者:M.-Lluïsa Bennasar、Ester Zulaica、Josep Bonjoch、Joan Bosch
DOI:10.1016/s0040-4020(01)80983-2
日期:1991.7
Tetracyclic keto lactam 2a has been synthesized by acyladon of a mixture of esters 5, followed by saponification and further cyclization. Due to the presence of an exocyclic amide carbonyl group, epimerization at C-3 occurs to give the most stable cis relative configuration. Trans acetylpiperidine 4b has been prepared in five steps from pyridinium salt 9. Attempted direct cyclization of 4b to epingouniensine
四环酮内酰胺2a已经通过酯5的混合物的酰基丙啶进行合成,随后进行皂化和进一步环化。由于存在环外酰胺羰基,因此在C-3处发生差向异构,以提供最稳定的顺式相对构型。由吡啶鎓盐9分五个步骤制备了反式乙酰基哌啶4b。尝试将4b直接环化为epingouniensine失败。