A biomimetic three-step transformation of classical "6-6-6-5"-steroids into their C-nor-D-homo-counterparts gives an easy and fast access to this highly important substructure of natural products, as it is found in cyclopamine, and nakiterpiosin. A novel reagent combination allows for the rearrangement even of 17-keto steroids with high endoselectivity. In several examples the broadness of this strategy
将经典的“6-6-6-5”-类
固醇仿生三步转化为它们的 C-nor-D-homo-对应物,可以轻松快速地获得这种非常重要的
天然产物子结构,如在
环巴胺和纳克特皮辛。一种新的试剂组合允许甚至具有高内选择性的 17-
酮类固醇的重排。在几个示例中,概述了该策略的广泛性。