Palladium‐catalyzed base‐selective annulation of dibromonaphthalimide to different aryl boronate esters by combined Suzuki–Miyaura cross‐coupling and direct C−H arylation afforded a series of new five‐ and six‐membered ring annulated electron‐poor polycyclic aromatic hydrocarbons. Cesium carbonate (Cs₂CO₃) as auxiliary base in these C−C coupling cascade reactions led exclusively to six‐membered ring annulation, while the use of organic base diazabicycloundecene (DBU) afforded the corresponding five‐membered ring annulated products. This base‐dependent selective mode of annulation is attributed to different mechanistic pathways directed by the applied base. The selective annulation was revealed by single crystal X‐ray analysis of the respective five‐ and six‐membered ring annulated products. The optical and redox properties of the new polycyclic aromatic dicarboximides were characterized by UV/Vis absorption and fluorescence spectroscopy and cyclic voltammetry.

中文翻译：

---

钯催化的CC偶联级联反应中的碱选择性五元环与六元环环化：电子贫多环芳族双碳酰亚胺的新途径

Suzuki-Miyaura交叉偶联和直接CHH芳基化反应使钯对二溴邻苯二甲酰亚胺的碱选择性环化成不同的芳基硼酸酯，提供了一系列新的五元和六元环化的电子贫化多环芳烃。碳酸铯（Cs ₂ CO ₃）作为这些C-C偶联级联反应的辅助碱仅导致六元环环化，而有机碱二氮杂双环十一碳烯（DBU）的使用提供了相应的五元环环化产物。这种依赖于碱基的环空选择模式归因于所应用的碱基所指导的不同机械途径。通过对五元和六元环空环化产品的单晶X射线分析揭示了选择性环空。通过紫外/可见吸收，荧光光谱和循环伏安法对新型多环芳族二羧酰亚胺的光学和氧化还原特性进行了表征。