Nguyen Tam, Wicki Markus A, Snieckus Victor
The Guelph-Waterloo Centre for Graduate Work in Chemistry, Department of Chemistry, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
J Org Chem. 2004 Nov 12;69(23):7816-21. doi: 10.1021/jo049890h.
A convergent synthesis of the A/B/C/D ring fragment 5 of camptothecin using a combination of directed ortho metalation and Negishi cross-coupling is described. The key features of the synthetic sequence are an anionic ortho-Fries rearrangement (10 --> 12), a Negishi cross-coupling (7 --> 6), and a terminal modified von Braun reaction (16 --> 5) that leads to tetracyclic derivative 5 in 7 steps and 11% overall yield.
描述了一种使用定向邻位金属化和根岸交叉偶联相结合的方法对喜树碱A/B/C/D环片段5进行汇聚合成。合成序列的关键特征包括阴离子邻位弗里斯重排（10→12）、根岸交叉偶联（7→6）以及末端修饰的冯·布劳恩反应（16→5），该反应经过7步反应以11%的总收率得到四环衍生物5。
