Synthesis of Chromones via Palladium-Catalyzed Ligand-Free Cyclocarbonylation of o-lodophenols with Terminal Acetylenes in Phosphonium Salt Ionic Liquids

摘要

The highly efficient and selective palladium-catalyzed ligand-free cyclocarbonylation reaction of o-iodophenols with terminal acetylenes and CO in the phosphonium salt ionic liquid, C141-129(C6I113)3F+ Br-, affords diversified chromones in good to excellent yields under atmospheric CO pressure. The ionic liquid, as the reaction medium, enhances the efficiency of the cyclocarbonylation reaction.