Traditional and sustainable approaches for the construction of C-C bonds by harnessing C-H arylation.

Biaryl scaffolds are found in natural products and drug molecules and exhibit a wide range of biological activities. In past decade, the transition metal-catalyzed C-H arylation reaction came out as an effective tool for the construction of biaryl motifs. However, traditional transition metal-catalyzed C-H arylation reactions have limitations like harsh reaction conditions, narrow substrate scope, use of additives etc.

Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites.

The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different fields, the associated reactivity and regioselectivity issues had rendered it redundant. The revival of this exemplary reaction requires the development of a mechanistic paradigm that would have simultaneous control on both the reactivity and regioselectivity.

Transient directing ligands for selective metal-catalysed C-H activation.

C-H activation is a 'simple-to-complex' transformation that nature has perfected over millions of years of evolution. Transition-metal-catalysed C-H activation has emerged as an expeditious means to expand the chemical space by introducing diverse functionalities. Notably, among the strategies to selectively cleave a particular C-H bond, the catalytic use of a small molecule as co-catalyst to generate a transient directing group, which provides a balance between step economy and chemical productivity, has gained immense attention in recent years.

Imine as a linchpin approach for meta-C-H functionalization.

Despite the widespread applications of C-H functionalization, controlling site selectivity remains a significant challenge. Covalently attached directing groups (DGs) served as ancillary ligands to ensure ortho-, meta- and para-C-H functionalization over the last two decades. These covalently linked DGs necessitate two extra steps for a single C-H functionalization: introduction of DG prior to C-H activation and removal of DG post-functionalization.