Recent Advances in Photoredox Catalysis Enabled Functionalization of α-Amino Acids and Peptides: Concepts, Strategies and Mechanisms

Dedicated to Professor Björn Åkermark on the occasion of his 85^th birthday

Published as part of the Bürgenstock Special Section 2018 Future Stars in Organic Chemistry

Abstract

The selective modification of α-amino acids and peptides constitutes a pivotal arena for accessing new peptide-based materials and therapeutics. In recent years, visible light photoredox catalysis has appeared as a powerful platform for the activation of small molecules via single-electron transfer events, allowing previously inaccessible reaction pathways to be explored. This review outlines the recent advances, mechanistic underpinnings, and opportunities of applying photoredox catalysis to the expansion of the synthetic repertoire for the modification of specific amino acid residues.

1 Introduction

2 Visible-Light-Mediated Functionalization of α-Amino Acids

2.1 Decarboxylative Functionalization Involving Redox-Active Esters

2.2 Direct Decarboxylative Coupling Strategies

2.3 Hypervalent Iodine Reagents

2.4 Dual Photoredox and Transition-Metal Catalysis

2.5 Amination and Deamination Strategies

3 Photoinduced Peptide Diversification

3.1 Gese-Type Bioconjugation Methods

3.2 Peptide Macrocyclization through Photoredox Catalysis

3.3 Biomolecule Conjugation through Arylation

3.4 C–H Functionalization Manifolds

4 Conclusions and Outlook

Key words

amino acids - electron transfer - peptides - photoredox catalysis - radicals - visible light

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