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.

用于开发否则为惰性的C–H键功能化的方法的开发是分子合成的主要重点之一。最近的进展显着改善了合成化学的技术，可使用功能化程度较低的原料，减少能源消耗并最大程度地减少废物产生。尽管取得了无可争议的进展，但与合成有意义的C–H活化相关的主要挑战是实现位置选择性。迄今为止，在过渡金属催化的分子间转化中解决位点选择性的最常用方法是通过导向基团的螯合辅助。这些指导小组的安装和撤消增加了额外的步骤，从而损害了整个CH活化策略的步骤经济性。相比之下，借助共催化添加剂对Lewis碱性实体进行现场安装和解构，以实现选择性的C–H官能化。