*Review***α-Functionalization of Imines via Visible Light Photoredox Catalysis** α

#### **Alberto F. Garrido-Castro 1 , M. Carmen Maestro 1, \* and José Alemán 1,2, \***


Received: 6 May 2020; Accepted: 16 May 2020; Published: 19 May 2020

**Abstract:** The innate electrophilicity of imine building blocks has been exploited in organic synthetic chemistry for decades. Inspired by the resurgence in photocatalysis, imine reactivity has now been redesigned through the generation of unconventional and versatile radical intermediates under mild reaction conditions. While novel photocatalytic approaches have broadened the range and applicability of conventional radical additions to imine acceptors, the possibility to use these imines as latent nucleophiles via single-electron reduction has also been uncovered. Thus, multiple research programs have converged on this issue, delivering creative and practical strategies to achieve racemic and asymmetric α-functionalizations of imines under visible light photoredox catalysis.

**Keywords:** amines; imines; photoredox catalysis; radical additions; radical–radical couplings; stereoselectivity; umpolung chemistry; visible light
