Water, Alcohols, Amines, and Amides as Formal Hydrogen‐Atom‐Transfer Reagents Through Activation With Redox‐Active Lewis Acids

Abstract

The O─H and N─H bonds of protic molecules such as water, alcohols, amines, or amides typically resist hydrogen-atom abstraction because of the high energy of the resulting heteroatom-centered radical intermediates. However, association of the protic molecules with redox-active Lewis acids provides stabilization of the generated reactive radical intermediates and enables the ligated protic molecules to serve as hydrogen-atom donors or proton-coupled-electron-transfer reagents. This review presents an overview of applications of this bond-weakening principle in organic synthesis and attempts to illustrate the breadth of systems that enable such reactivity.