Modular Synthesis of Multisubstituted Furans through Palladium-Catalyzed Three-Component Condensation of Alkynylbenziodoxoles, Carboxylic Acids, and Imines

Mild and regiocontrolled synthesis of a multisubstituted furan is achieved through Pd(OAc)₂-catalyzed room-temperature condensation of an alkynylbenziodoxole, a carboxylic acid, and an enolizable ketimine, which contribute to C1, CO, and C2 fragments, respectively, to the furan skeleton. The reaction tolerates a broad range of functional groups in each of the reaction components, and enables highly modular and flexible synthesis of variously substituted furans. The reaction is particularly effective for the rapid generation of tri- and tetraarylfurans and furan-containing oligoarylenes without relying on conventional cross-coupling chemistry.