Ruthenium(II)‐Catalyzed CH Activation/Alkyne Annulation by Weak Coordination with O 2 as the Sole Oxidant

Aerobic oxidative CH functionalizations of weakly coordinating benzoic acids have been accomplished with versatile ruthenium(II) biscarboxylates under ambient oxygen or air. Mechanistic studies identified the key factors controlling the elementary step of the oxidation of the ruthenium(0) complex.