# Deprotective Functionalization: An Emerging Concept for Amine Reactivity

## TL;DR

A new method called deprotective functionalization allows converting protected functional groups into new ones in a single step, avoiding the need for separate deprotection.

## Contribution

The novel approach of deprotective functionalization merges deprotection and functionalization into one step, using the protecting group to activate the target functionality.

## Key findings

- Deprotective functionalization reduces synthetic steps, cost, and waste in multi-step syntheses.
- The protecting group can prime the functional group for selective transformations without prior deprotection.
- This method is currently demonstrated for protected amines.

## Abstract

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.

While protecting groups are indispensable in total synthesis to avoid undesired reactivity, installation and removal of protecting groups lead to an increase in the step‐count, cost, waste production and time requirement. One approach tackling these drawbacks is deprotective functionalization, which combines deprotection and postfunctionalization in a single step, utilizing the protecting group to activate the functional group for further transformations.