A General Pd-Catalyzed\nC2–H Arylation of Benzoxazoles\nwith Highly Sterically Congested Aryl Chlorides Enabled by a Fittingly\nTuned Ligand

The\nbenzoxazole core, featuring a sterically congested 2,6-disubstituted\naryl fragment at the C2 position, exhibits exclusive three-dimensional\nstructures that are essential for particular applications in material\nscience and pharmaceutical development. Despite their importance,\nthe synthesis of these compounds has posed challenges with an efficient\npreparation strategy still lacking. In this study, we introduced a\nnew indolylphosphine ligand, <b>PCy</b><sub><b>2</b></sub><b>-Man-phos</b>, specifically designed to facilitate the C2–H\narylation of benzoxazoles with sterically hindered aryl chlorides\nin general. The excellent functional group compatibility and rich\narene substituted pattern enable the creation of highly decorated\nand sterically demanding 2-arylbenzoxazole frameworks, showing significant\npotential for diverse synthetic applications.