Directed <i>o</i><i>rtho </i>Metalation Approach to C-7-Substituted Indoles. Suzuki−Miyaura Cross Coupling and the Synthesis of Pyrrolophenanthridone Alkaloids
作者:Christian G. Hartung、Anja Fecher、Brian Chapell、Victor Snieckus
DOI:10.1021/ol0344772
日期:2003.5.1
overall yields. In combination with the Suzuki-Miyaura protocol, C-7 aryl (heteroaryl)-substituted indoles 14 and 16 are obtained, including hippadine and pratosine, members of the pyrrolophenanthridone alkaloid family.
[反应:见正文]尽管吲哚N-膦酰基衍生物4经过n-BuLi脱质子/亲电淬灭以提供C-7取代的产物,但其脱保护需要苛刻的条件。另一方面,N-酰胺12经连续或一锅C-2金属化,甲硅烷基化,C-7金属化和亲电处理后,以良好的总收率提供吲哚7。与Suzuki-Miyaura规程结合使用,可获得C-7芳基(杂芳基)取代的吲哚14和16,包括吡咯并菲蒽酮生物碱家族的成员Hippadine和pratosine。