Stille Cross-Coupling for the Functionalization of the Imidazole Backbone: Revisit, Improvement, and Applications of the Method
作者:Alexander H. Sandtorv、Karl Wilhelm Törnroos、Hans-René Bjørsvik
DOI:10.1002/ejoc.201500328
日期:2015.6
We have revisited the Stille coupling reaction for the functionalization of the imidazole backbone. In this context CuI was exploited as a co-catalyst, which resulted in significantly improved yields of target coupling products. Furthermore, a systematic investigation of the effect of the auxiliary group on the N-1-ring atom was performed. When mono-coupling is desired, the Tosyl (Tos) group is superior
我们重新审视了用于咪唑骨架功能化的 Stille 偶联反应。在这种情况下,CuI 被用作助催化剂,从而显着提高了目标偶联产物的产率。此外,还对辅助基团对 N-1 环原子的影响进行了系统研究。当需要单偶联时,甲苯磺酰基 (Tos) 基团优于(二甲氨基)磺酰基 (DMAS) 基团,以显着更高的产率提供相应的 4 偶联咪唑。然而,当首选双耦合时,DMAS 组对于耦合程序的成功是必不可少的。利用该反应协议,我们成功地展示了使用 N-DMAS-4,5-二碘咪唑作为底物的 Stille 双偶联的第一个例子。