Direct synthesis of benzofuro[3,2-b]benzofurans via a palladium-catalyzed dearomative cyclization

A palladium-catalyzed dearomative [3+2] cycloaddition of benzofurans with 2-iodophenols to produce benzofuro [3,2-b]benzofurans is described.This approach employs Pd(OAc)2 as the catalyst and Ag2O as the oxidant in HFIP as the solvent with NaOAc as the base.This straightforward and highly atom-economical method affords moderate to excellent yields and tolerates a range of functional groups.A plausible mechanism involving a Pd(0/II) catalytic cycle is proposed.