Organocatalytic Synthesis of Amides Using Thioacids and Anilines via Electron Donor–Acceptor Photoactivation

Amides are important structures with relevance in biology, material science, and synthetic chemistry. Their photochemical synthesis via aminolysis of acetyldisulfides relies on a reductive regime of thioacids using transition metal-based photocatalysts and organic dyes. Here, we report that readily available tetrachlorophthalimide can serve as an organocatalytic acceptor to thioacids for the electron donor-acceptor (EDA) photoactivation, thereby generating the desired thioacyl radicals suitable for dimerization and, subsequently, amidation via aminolysis. The usefulness of this EDA platform enabled us to develop and demonstrate a mechanistically distinct synthesis of sterically and electronically diverse amides using thioacids as acyl sources, with isolated yields of up to 97%. Furthermore, the reactions proved to be efficient and easy to operate as they could be conducted under an open-air atmosphere, eliminating the need to create a rigorous inert atmosphere. Notably, the gram-scale synthesis of paracetamol was achieved using the developed photochemical transformation.