Deprotective Functionalization: An Emerging Concept for Amine Reactivity.

Protecting groups are widely employed in multi-step syntheses with the goal to downregulate the reactivity of certain functional groups. Their use, while often unavoidable, comes with notable drawbacks including increased costs and waste, as well as typically adding two (nonstrategic) synthetic steps to a given sequence. Moreover, late-stage deprotection of highly functionalized compounds can pose challenges. We introduced an approach termed deprotective functionalization, allowing for direct conversion of a protected functional group into a new one without requiring a separate deprotection event. Interestingly, in this paradigm the protecting group not only prevents side reactions, but also primes the protected functionality for selective transformations. This article provides a conceptual framework for this approach and discusses related strategies, currently limited to protected amines.