LAUSR

Bismuth(III) oxide has been successfully applied as a photocatalyst in the arylation of heteroarenes with diazonium salts. With a low catalyst loading (1 to 5 mol%), this cheap and non-toxic semiconductor could efficiently promote the formation of the aryl radical under visible light irradiation. The arylated products are obtained in moderate to good yields, and the the process admits straightforward scale-up (10 mmol; 1 mol% Bi2O3). In two cases, the diazonium salt was generated in situ and used in the photocatalytic arylation in a tandem manner. Besides heteroarenes, Bi2O3 proved also to catalyze the arylation of differently substituted alkenes and alkynes, thus representing a viable and practical alternative to the more commonly used ruthenium complexes and organic dyes