Access to Electron‐Rich Dibenzofurans through NBu4OAc‐Mediated Palladium Catalysis

Dibenzofuran and its derivatives are ubiquitous and important medicinal and natural products. Many contain electron‐rich aryl rings. Forming the key intramolecular Ar−Ar bond using traditional cross‐coupling is difficult. The C−H functionalisation (C−H activation) approach is, in principle, far more useful. However, we previously found that the well‐established conditions, which promote C−H functionalisation through Concerted Metalation‐Deprotonation (CMD), proved unsatisfactory. Herein, we report a Pd‐catalysed C−H functionalisation protocol that works with electron‐rich arenes. We use tetrabutylammonium acetate (NBu4OAc), which we suspect can act as base, ligand and solvent, rendering this protocol a simple and efficient route to electron‐rich dibenzofurans. Dibenzofuran and its derivatives are ubiquitous and important medicinal and natural products. Many contain electron‐donating substituents. Herein, we report a Pd‐catalysed C−H functionalisation protocol that works with electron‐rich arenes. We use tetrabutylammonium acetate (NBu4OAc), which we suspect can act as base and ligand, rendering this protocol a simple and efficient route to dibenzofurans.