Redox Properties of Catalytically Generated Iminium Ions From α,β‐Unsaturated Aldehydes and Chiral Secondary Amines

Chiral iminium ions are key catalytic intermediates in aminocatalysis, enabling a wide range of enantioselective transformations. Yet, a systematic study of how their electrochemical properties vary as a function of the different reaction components has remained elusive, largely due to their transient nature and inherent instability. Herein we show a general protocol for the catalytic generation and in situ cyclic voltammetric characterisation of over 50 chiral iminium ions. This analysis reveals how the catalyst electronics, aldehyde nature and substitution, and the solvent environment governs their reduction potential. This electrochemical mapping provides predictive insights into iminium ion reactivity via single‐electron transfer, laying the groundwork for the rational design of novel radical‐based asymmetric transformations.