Multicomponent Reactions Enabled by Photoinduced Formal Alkyl Transfer of Tertiary Amines

Abstract

Multicomponent reactions (MCRs) provide a powerful and efficient strategy for rapidly accessing structurally diverse compounds under mild conditions. Among MCRs, the Ugi‐type reactions—including the Ugi–azide variant—hold a central role in the synthesis of α‐amino derivatives. Historically, research in this area has largely focused on expanding the scope of nucleophiles to access novel and complex products. However, most reported transformations still rely on imine (or iminium) intermediates generated from primary/secondary amines and aldehydes/ketones. In this work, we disclose a photochemical approach that utilizes photoexcited aromatic amines to trigger the oxidation of tertiary amines, leading to the formation of iminium species. These intermediates undergo a formal alkyl transfer process with aromatic amines to generate new iminium salts, which subsequently engage with various nucleophiles in a multicomponent fashion. This strategy enables the efficient synthesis of three important classes of functional molecules—α‐amino phosphine oxides, tetrazoles, and imides—via a tertiary amine‐involved MCR under light irradiation.