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

• Published in: European journal of organic chemistry 2023-11, Vol.26 (44), p.n/a
• Main Authors: Power, Mark, Mackey, Katrina, Light, Mark E., Jones, David J., McGlacken, Gerard P.
• Format: Article
• Language: English
• Subjects: Aromatic compounds; catalysis, tetraalkylammonium salt; Cross coupling; Dibenzofuran; electron-rich; Natural products; Palladium
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.202300790

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.