Synthesis of novel, simplified, C-7 substituted eleutheside analogues with potent microtubule-stabilizing activity
作者:Damiano Castoldi、Lorenzo Caggiano、Pau Bayón、Anna M. Costa、Paolo Cappella、Ofer Sharon、Cesare Gennari
DOI:10.1016/j.tet.2004.12.039
日期:2005.2
The synthesis of a number of novel, simplified, C-7 substituted eleutheside analogues with potent tubulin-assembling and microtubule-stabilizing properties is described, using ring closing metathesis as the key-step for obtaining the 6–10 fused bicyclic ring system. The RCM precursors were synthesized starting from aldehyde 3 [prepared in six steps on a multigram scale from R-(−)-carvone in 30% overall
描述了许多具有有效的微管蛋白组装和微管稳定特性的,新颖的,简化的,C-7取代的荧光苷类似物的合成,使用闭环易位作为获得6-10稠合双环系统的关键步骤。RCM前体是通过多个立体选择性的Hafner-Duthaler烯丙基钛化和/或Brown烯丙基硼酸酯化反应从醛3 [从R -(-)-香芹酮以克数分六步制备的,总产率为30%]合成的。“第二代” RCM催化剂15以良好的收率得到了所需的闭环十元碳环,为单Z立体异构体。RCM立体化学过程(100%Z)可能反映了热力学控制。分子力学和半经验计算还表明,这些十元碳环的Z立体异构体始终比E稳定。讨论了均烯丙基和烯丙基取代基及其保护基对于RCM反应效率的关键作用。特别地,我们已经发现,对-甲氧基苯基(PMP)保护的烯丙基醇,立体选择性氧化烯丙基化的产物,与RCM反应相容,并且比相应的游离烯丙基醇具有更好的产率。天然产物的简化类似物之一(44,尤其缺乏C-4