Ruthenium-Catalyzed meta-Selective CH Bromination

The first example of a transition‐metal‐catalyzed, meta‐selective CH bromination procedure is reported. In the presence of catalytic [{Ru(p‐cymene)Cl2}2], tetrabutylammonium tribromide can be used to functionalize the meta CH bond of 2‐phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility with one‐pot bromination/arylation and bromination/alkenylation procedures to deliver meta‐arylated and meta‐alkenylated products, respectively, in a single step. Taking position: 2‐Phenylpyridines undergo meta‐selective bromination using tetrabutylammonium tribromide under ruthenium catalysis, thus affording products that are highly predisposed to further derivatization. The bromination can be combined with arylation and alkenylation chemistry to access meta‐arylated and meta‐alkenylated products, respectively, in a one‐pot operation.