Domino C-C/C-O bond formation: palladium-catalyzed regioselective synthesis of 7-iodobenzo[]furans using 1,2,3-triiodobenzenes and benzylketones.

A facile and efficient synthesis of 7-iodobenzo[]furan derivatives a highly regioselective tandem α-arylation/intramolecular -arylation of 5-substituted-1,2,3-triiodobenzenes and benzylketones is described. Remarkably, the α-arylation coupling reactions initiate exclusively at the least sterically-hindered position of the triiodoarene, which results in a highly chemoselective transformation. The highest yields were observed in reactions between electron-poor 1,2,3-triiodoarenes and electron-rich benzylketones, yet the optimized reaction conditions were found to be tolerant to a wide range of different functional groups. This unprecedent synthesis of 7-iodobenzo[]furans from 1,2,3-triiodobenzenes is scalable, general in scope, and provides easy access to valuable precursors for other chemical transformations.