Intramolecular Catalyst Transfer over Sterically Hindered Arenes in Suzuki Cross-Coupling Reactions

The intramolecular catalyst transfer over sterically hindered arenes in Suzuki cross-coupling reaction was investigated by the reaction of ortho-substituted dibromoarenes with equimolar ortho-substituted phenylboronic acid in the presence of NHC based PEPPSI-IPr as catalyst. The diarylarene species of the form Ar'-Ar-Ar' were observed as major product, which suggested the intramolecular transfer of Pd(0) over sterically hindered arenes proceeded smoothly in Suzuki cross-coupling reaction. Furthermore, our studies also demonstrated that intramolecular catalyst transfer could be a useful tool to improve the polymerization efficiency, especially in the synthesis of ortho-linked polyarenes.