Transition-metal-free tunable regioselective [3+2] cycloaddition of diaryliodonium salts with 1,3-dicarbonyl derivatives

A new [3+2] cycloaddition reaction of diaryliodonium salts with 1,3-dicarbonyl compounds for the synthesis of benzofuran derivatives is reported, involving the sequential selective coupling of dual electrophilic and nucleophilic reagents. The key to this reaction is the use of a novel diaryliodonium reagent, which carries both a leaving group and a strong electron-withdrawing group (EWG). Interestingly, the choice of leaving group can dictate the reaction's selectivity. Moreover, the protocol demonstrates significant robustness, flexibility, and compatibility with a broad range of functional groups.