Palladium-Catalyzed Chemo- and Regiocontrolled Tandem Cyclization/Cross-Coupling of 2-Benzyl-3-alkynyl Chromones with Aryl Iodides for the Synthesis of 4H-Furo[3,2-c]chromenes and Xanthones

A novel Pd-catalyzed chemo-and regiocontrolled tandem cyclization/cross-coupling reaction of 3-alkynyl chromone with aryl iodide was developed for the synthesis of 4H-furo[3,2-c]chromenes and xanthones. The difunctionalization of alkynes through O-attack/5-exo-dig and C-attack/6-endo-dig cyclization was reported by this rare approach, which was selectively controlled by the addition of KF or a bidentate phosphine ligand. A one-pot tandem process was demonstrated directly from gamma-alkynyl-1,3-diketone for this method.

Automated summary

A novel Pd-catalyzed reaction was developed for the synthesis of 4H-furo[3,2-c]chromenes and xanthones through tandem cyclization/cross-coupling reaction of 3-alkynyl chromone with aryl iodide. The reaction selectively controlled by KF or a bidentate phosphine ligand exhibited a rare difunctionalization of alkynes through O-attack/5-exo-dig and C-attack/6-endo-dig cyclization. A one-pot tandem process was demonstrated directly from gamma-alkynyl-1,3-diketone for this method.