Remote ‘Imidazole’ Based Ruthenium(II) p‐Cymene Precatalyst for Selective Oxidative Cleavage of C−C Multiple Bonds

Abstract The dual role of remote ‘imidazole’ attached with the precatalyst [( p ‐cymene)Ru II (L)Y] + (L=2‐(4‐substituted‐phenyl)‐1H‐imidazo[4,5‐f][1,10] phenanthroline, Y=chloride/solvent) was explored for the selective oxidative cleavage of C−C multiple bonds to acetals/aldehydes. The presence of ‘imidazole’ in the precatalysts was found to be useful for the activation of oxidant and release of p ‐cymene from the precatalysts, which in turn was not effective without the ‘imidazole’ moiety. The mechanistic aspects of the precatalyst were evaluated from spectroscopic, kinetic, and few other controlled experiments. The loss of p ‐cymene is the key step for the reaction and found to be faster in solvated precatalyst, [( p ‐cymene)Ru II (L)(MeOH)] ++ and thus showed 3–4‐fold more effective as compared to [( p ‐cymene)Ru II (L)Cl] + .