A Self‐Sustaining Supramolecular (Auto)Photocatalysis via the Synthesis of N ‐Vinylacetamides

Abstract Efforts to enhance photocatalysts prioritize improving their accessibility and practicality in photocatalytic applications. Supramolecular (auto)photocatalysis, which exploits transient self‐assembled complexes, facilitates visible light‐driven reactions, with autocatalytic systems promoting sustainable and atom‐economical processes. In this study, the photocatalyst Mes‐Acr‐MeClO 4 , typically active under blue light, formed a dark red charge‐transfer (CT) complex with N ‐bromoacetamide (NBA) in the presence of K 2 CO 3 in DCE, enabling green‐light photocatalysis. This self‐assembled CT complex initiated an auto‐photocatalytic process via two‐photon absorption, generating an N ‐centered radical that drove anti ‐Markovnikov, syn ‐periplanar addition to phenylacetylene, achieving exclusive Z ‐selective formation of ( Z )‐ N ‐(2‐bromo‐2‐phenylvinyl)acetamide. Interestingly, the product itself functioned as a potent green‐LED photocatalyst (λ em = 518 nm, τ = 10 ns), driving its own synthesis with added terminal alkynes. With 100% atom economy, this work highlights a system chemistry approach, showcasing a highly efficient, self‐sustaining catalytic process that advances green and sustainable synthetic strategies. This protocol emphasizes sustainability with an outstanding E‐factor of 11.15, reflecting minimal waste production (11.15 kg per 1 kg of product) and demonstrating a strong commitment to green chemistry principles.