Nickel‐Catalyzed Decarbonylative Cycloaddition of Benzofuran‐2,3‐diones with Alkynes to Flavones

Using dppe as the ligand, the Nickel‐catalyzed decarbonylative cycloaddition of benzofuran‐2,3‐diones with alkynes was established, and a variety of functional flavones were synthesized in 65–99% yields. Terminal alkynes with substituted phenyl groups and internal alkynes such as aryl acyl acetylenes and diphenylacetylenes are suitable for this reaction. The effects of bases on the reactions of different types of alkyne substrates were also investigated and discussed.