Ruthenium Metal: Uplifting Regioselective C-H activation

: Construction of the C-C bond has always been a challenge for organic chemists, because of the reactivity of carbon atoms. The making of nucleophilic carbon started with the Grignard reagent, enolate, and the ylide, moreover, the aromatic carbon activation was the challenge before the era of organometallic chemistry. The recognition of organometallic chemistry was in the light when the Nobel Prize was given for the C-C bond in the year 2010, However, The pre functionalization of the C-H bond was an additional step with halogenated reagent, which was the limitation of this reaction. Later the C-H activation with organometals like Pd, Ru, Cu, Rh, and other transition metal came into existence, where the directing group and metal makes feasibility to form the nonreactive C-C bond. In spite of several organometals, Ru made a special place due to the reactivity, coast and, stability. Various C-H activation reaction protocols were reported with their high regioselectivity as well as high atom economy. The C-H activation protocol is now in the next level of development like SP3, SP2 ortho, meta, and para C-H activation. Here in our aim is to get the summarized information regarding the Ru and their ortho -regioselective reactions with the help of the directing group. The reader will be benefited from the mechanistic part and the concept of C-H activation with some of the important examples, which have been summarized here in with the various Ru based regioselective reactions through weak and strong coordination of metal and substrate.