Synthesis of the AB-DE Ring System Present in the Alstoscholarine Alkaloids
作者:Luis Miranda、Luis Polindara-García
DOI:10.1055/s-0031-1289745
日期:2012.4
A practical protocol is presented for the construction of the AB-DE rings present in (19,20)-(E)- and (19,20)-(Z)-alstoscholarine alkaloidsfrom the commercially available glutamic acid 5-methyl ester, employing only a six-step synthetic sequence. The main features include the synthesis of the alkynylindolizinone core and the use of Sonogashira cross-coupling and base-mediated cyclization to afford