Table 1.

Optimization of reaction conditions.^a

^aReaction conditions: photocatalyst (3 mol%), NiCl₂•glyme (20 mol%), dtbbpy (20 mol%), alkyne (0.1 mmol), oxalate (1.5 equiv.), aryl bromide (2.0 equiv.), DMSO [0.05 M], 90 W blue LED, 36 °C, 18 h. Yields determined by ¹H NMR with an internal standard, and the ratio of the two isomers was determined by ¹H NMR analysis of the crude reaction mixture. dtbbpy = 4,4′-di-tert-butyl-2,2′-dipyridyl; 4CzlPN = 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile