Ruthenium‐Catalyzed ortho ‐CH Bond Arylation Reactions

Abstract

The highly selective ruthenium-catalyzed ortho-C-H bond arylations have met a level of maturity that makes them an attractive tool to achieve unique organic transformations.By means of the manifold mechanisms operating in the presence of different arylating agents and reaction conditions, these methodologies have succeeded in reducing the wastes/steps towards the desired molecules as well as enlarging the chemical space by affording molecules impossible to obtain otherwise. The key achievements in this area are discussed in this chapter. Introduction.Biaryl and terphenyl cores are widespread structures in many biologically active substances and have useful physical properties in material sciences. The seminal results on the synthesis of biphenyl by connecting two aryl iodide molecules via reductive coupling in the presence of copper were reported in 1901 [1] and this concept was further developed [2,3]. Since this discovery, continuous efforts have been devoted to the improvement of these aryl-aryl couplings, mainly based on palladium-catalyzed cross-coupling reactions of aryl (pseudo)halides with organometallic reagents leading to the formation of a new C(sp 2 )-C(sp 2 ) bonds (Figure 1a) [4][5][6][7][8].