C-H Functionalization Reactions of Phenyl and Vinyl Carbocations Paired with Weakly Coordinating Anions

Carbocations have played a central role in the chemical sciences for over a century. In a synthetic setting, most methods utilize stabilized tricoordinate carbocations, while there are far fewer examples of reactions featuring nonstabilized dicoordinate cations. Here, we provide an overview of recent developments in the generation of high-energy carbocations mediated by weakly coordinating anions and the C-H insertion reactions of such carbocations. Moreover, we discuss mechanistic studies of these catalytic C-H insertion reactions aimed at furthering our understanding of the reactive nature of these rarely invoked cationic intermediates. 1 Introduction 2 Background: Phenyl Carbocations 3 Silylium/Carborane-Catalyzed C-H Insertion Reactions of Phenyl Carbocations 4 Silane-Fueled, Weakly Coordinating Anion-Catalyzed, Reductive C-H Insertion Reactions of Vinyl Carbocations 5 C-H Insertion Reactivity of Vinyl Carbocations under Basic Conditions 6 Conclusion and Outlook