Late‐Stage C─N Bond Cleavage Enables Diversification of Multiple Resonance Materials

Abstract

Abstract Recent advances in materials development for organic light‐emitting diodes (OLEDs) have been driven by an emerging design concept known as multiple‐resonance (MR), which provides the benefits of high efficiency and color purity required for commercial OLED displays. Borylation reaction constructing MR frameworks is a key step for developing new π‐conjugated systems, while this reaction includes the limitation of selectivity, making it challenging to control reactions in elaborate molecular structures. Although a wide variety of MR compounds have been prepared through carefully planned synthetic schemes based on retrosynthetic analysis, these tasks typically require significant effort for each individual target. Herein, we demonstrate a successful late‐stage functionalization strategy that enables structural modifications after the borylation reaction, especially in hardly accessible regions in MR structures via carbon–nitrogen bond cleavage. Our new synthetic method also allows access to new products which were never feasible before. The newly developed material, DABNA‐dimer , proves the impact of late‐stage functionalization on OLED characteristics. The present study serves as a proof‐of‐concept for a diversity‐orientated synthesis in the development of MR materials.