Department of Chemistry, University of Georgia, Athens, GA 30602, USA.
Angew Chem Int Ed Engl. 2022 Nov 7;61(45):e202212187. doi: 10.1002/anie.202212187. Epub 2022 Oct 11.
A direct dearomative photocatalyzed (3+2) cycloaddition between indoles and vinyldiazo reagents is described. The transformation is enabled by the development of a novel oxidizing Cr photocatalyst, its specific reactivity attributed to increased absorptive properties over earlier Cr analogs and greater stability than Ru counterparts. A variety of fused indoline compounds are synthesized using this method, including densely functionalized ring systems that are feasible due to base-free conditions. Experimental insights corroborate a cycloaddition initiated by nucleophilic attack at C3 of the indole radical cation by the vinyldiazo species.
本文描述了吲哚和乙烯基重氮试剂之间的直接去芳构化光催化（3+2）环加成反应。通过开发新型氧化铬光催化剂实现了这种转化，其特定的反应性归因于对早期铬类似物的吸收特性增强和比钌类似物更高的稳定性。该方法合成了多种稠合吲哚啉化合物，包括由于无碱条件而可行的多官能化环系统。实验结果证实了由吲哚自由基阳离子的 C3 上的亲核进攻引发的环加成反应。
