Mechanochemical borylation of aryldiazonium salts; merging light and ball milling (Beilstein Journal of Organic Chemistry)

Abstract Merging of photo- and mechanochemical activation permitted studying the role of eosin Y in the borylation of aryldiazonium salts in a ball mill. Simultaneous neat grinding/irradiation of the reactants and the photocatalyst led to the formation of boronates in a molten state. On the other hand, the catalyst-free liquid-assisted grinding/irradiation reaction also led to product formation, featuring a direct photolysis pathway facilitated by substrate–solvent charge-transfer complex formation. Beilstein J. Org. Chem. 2017, 13, 1463–1469. doi:10.3762/bjoc.13.144