Rapid Room-Temperature, Chemoselective Csp2 -Csp2 Coupling of Poly(pseudo)halogenated Arenes Enabled by Palladium(I) Catalysis in Air.

While chemoselectivities in Pd -catalyzed coupling reactions are frequently non-intuitive and a result of a complex interplay of ligand/catalyst, substrate, and reaction conditions, we herein report a general method based on Pd that allows for an a priori predictable chemoselective Csp2 -Csp2 coupling at C-Br in preference to C-OTf and C-Cl bonds, regardless of the electronic or steric bias of the substrate. The C-C bond formations are extremely rapid (<5 min at RT) and are catalyzed by an air- and moisture-stable Pd dimer under open-flask conditions.