LAUSR

Summary The development of methods for the functionalization of otherwise inert C–H bonds is one of the major foci in molecular syntheses. Recent advances have significantly improved the arsenal of synthetic chemistry, enabling the use of less functionalized starting materials, a reduction of energy consumption, and a minimization of waste production. Despite undisputable progress, the main challenge associated with synthetically meaningful C–H activations is achieving positional selectivity. Thus far, the most common approach to address site selectivity in transition-metal-catalyzed intermolecular transformations is constituted by chelation assistance through directing groups. The installation and removal of these directing groups adds additional steps, compromising the step-economical nature of the overall C–H activation strategy. In contrast, here we discuss the emergence of transient directing group approaches through the in situ installation and deconstruction of a Lewis-basic entity with the aid of co-catalytic additives for selective C–H functionalizations.