Alkaline Transition Metal‐Free Oxidative Coupling of Benzylic and Quasi Benzylic sp³ Bonds with O₂

Abstract An in‐situ strategy is reported for the transition‐metal‐free oxidation of a benzylic H‐pair to perform Csp 3 −Csp 3 bond formation. This study used sixteen benzylic and quasi benzylic reactants of primary and secondary alkyl aryl compounds, e. g., toluene, pyridine, and quinoline derivatives, to perform an oxidative coupling reaction via convenient air oxygen (O 2 ) and MeOH‐KOH solution with a yield of 0–98 %. We now report using an in‐situ green transition‐metal‐free oxidative coupling strategy for C−C bond formation. In other attempts, metal‐catalyzed oxidation of the benzylic sp 3 C−H bond of the methylquinoline has been done to perform the sp3 functionalization reaction. The reaction of 2‐methylqunioline with phenylacetylene in the presence of CuCl catalyst completed to isoxazole linkage product.