A Remote ‘Imidazole’‐Based Ruthenium(II) Para‐Cymene Pre‐catalyst for the Selective Oxidation Reaction of Alkyl Arenes and Alcohols

Herein we disclosed the use of a remote ‘imidazole’‐based precatalyst [(para‐cymene)RuII(L)Cl]+, C‐1 where L=2‐(4‐substituted‐phenyl)‐1H‐imidazo[4,5‐f][1,10] phenanthroline) for the selective oxidation of a variety of alkyl arenes/heteroarenes and alcohols to their corresponding aldehydes or ketones in presence of tert‐butyl hydroperoxide (TBHP). The remote ‘imidazole’ moiety present in the complex facilitates the activation of oxidant and subsequent generation of active species via the release of para‐cymene from C‐1, which in‐turn was less effective without the ‘imidazole’ moiety. The mechanistic features of C‐1 promoted oxidation of alkyl arenes were also assessed from spectroscopic, kinetic, and few control experiments. The substrate scope for C‐1 promoted oxidation reaction was assessed based on the selective oxidation of 27‐different alkyl arenes/heteroarenes and 25 different alcohols to their corresponding aldehydes/ketones in moderate to good yields. The dual role of remote ‘imidazole’ attached with the precatalyst [(η6‐p‐cymene)RuII(L)Cl]+ (L=2‐(4‐substituted‐phenyl)‐1H‐imidazo[4,5‐f][1,10] phenanthroline) for the activation of oxidant (tert‐butyl hydroperoxide, TBHP) and generation of active catalyst via the release of para‐cymene for the selective oxidation of 27‐different alkyl arenes/heteroarenes and 25 different alcohols to their corresponding aldehydes/ketones in moderate to good yields is disclosed.