Visible Light‐Triggered Radical Annulation of <i>ortho</i>‐Thioaryl Ynones: A General Approach to Prepare 3‐Sulfenylthiochromones
Ricardo H. Bartz, Krigor B. Silva, Rafaela R. S. A. Santos, Thiago J. Peglow, Eder J. Lenardão, Bernardo A. Iglesias, Filipe Penteado, Gelson Perin, Raquel G. Jacob
Abstract
Abstract A visible light‐mediated protocol was developed for the construction of 3‐sulfenylthiochromenones by a radical annulation of ortho ‐thioaryl ynones. The reaction is triggered by a sulfur‐centered radical, which is formed through the light excitation of an intramolecular electron donor‐acceptor complex (EDA‐complex). A total of twenty‐one compounds were prepared, in poor to excellent yields (28–98 %), sixteen of which are unprecedented. The reactions were conducted under open‐air conditions, not requiring metal catalysts, oxidant species, or heating, making this a mild and environmentally friendly approach to access valuable compounds.