Photocatalytic Synthesis of Stilbenes via Cross‐Coupling of Alkenyl Boronic Acids and Arenediazonium Tetrafluoroborate Salts

Abstract

AbstractIn this article, we describe the development of a new method for the photocatalytic synthesis of (E)‐stilbenes by the coupling of alkenyl boronic acids and aryldiazonium salts. In our operatively simple and metal‐free system, visible light is used as an energy source and a “green” mixture of water and ethanol is used as solvent. A mechanistic explanation is presented which is supported by several control experiments. The reaction proceeds via a radical pathway, from both the diazonium salt and boronic acid in the presence of visible light.