Sustainable Ruthenium(II)-Catalyzed C-H Activations in and on H2O

Catalyzed C-H activation has surfaced as an enabling tool for molecular assembly, with a plethora of translational applications. The enormous developments toward the utilization of ubiquitous C-H bonds as latent functionalities has thus enabled the efficient assembly of increasingly complex scaffolds. Recently, a paradigm shift has occurred to enable sustainable, industry-relevant C-H functionalization manifolds. Among the most prominent transition metals for C-H activations, ruthenium offers several salient features, including cost-effective, robust, and mild C-H activations with unique reactivities for remote functionalization. Indeed, ruthenium(II) catalysis by carboxylate assistance offers a highly functional group tolerant and predictable toolbox for directed as well as nondirected C-H functionalizations, with a major impact to improve the sustainability in industrial settings. These assets have allowed the use of nontoxic, nonflammable, and cost-effective H2O as a reaction medium for sustainable ruthenium(II)-catalyzed C-H activations. In this perspective, we summarize the potential of water for sustainable ruthenium(II)-catalyzed C-H activations up to February 2022.