Functionalization of bicyclic N-acylhemiaminals, which are readily available by titanium-mediated intramolecular coupling of vinyl-tethered imides, has been achieved by use of the Nazarov cyclization to construct the carbon-carbon bond at the quaternary center. This synthetic strategy allows rapid entry to the key structural elements of cephalotaxine.
                                    已实现对双环N-酰基半胺的功能化,这些化合物可以通过
钛介导的
乙烯连接的酰胺的分子内偶联容易获得,使用Nazarov环化反应在四级中心构建碳-碳键。这一合成策略使我们能够快速进入颅税素的关键结构元素。