Pd/Cu Co‐Catalyzed ortho‐Arylation of Aryl Iodides via Radical Intermediates with Aryl Diazonium Salts.

A Cu/Pd co‐catalyzed Catellani‐type ortho arylation reaction of iodoarenes with aryl diazonium salts has been developed. Aryl radicals that derived from aryl diazonium salts were regioselectively installed at ortho position of iodoarenes via palladium catalyzed C−H activation. Mechanistic studies showed that, in contrast to classical Pd0−PdII−PdIV−PdII−Pd0 catalytic cycle, this radical cascades performed via a Pd0−PdII−PdIII−PdI−Pd0 cycle. [ABSTRACT FROM AUTHOR]