Visible‐Light‐Mediated Photocatalytic Synthesis of 2‐Substituted Oxazole‐5‐carbaldehydes Promoted by Benzeneseleninic Acid

Abstract

Abstract Benzeneseleninic acid was used under visible light irradiation (white LEDs) to promote the oxidative cyclization of N ‐propargyl amides to the respective 2‐substituted oxazole‐5‐carbaldehydes. A total of twelve 2‐aryl oxazole‐5‐carbaldehydes, six of them so far unprecedented, were prepared in 30–90 % yield in just 1 hour of reaction at room temperature. No metal catalysts, nor strong oxidants or heating were necessary, making this a mild method to access a valuable class of compounds. The only co‐products are water and diphenyl diselenide, that can be recovered and converted to new benzeneseleninic acid for a new reaction.

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