Palladium-Catalyzed Regioselective Benzylic C(sp3 )-H Alkylation in Aromatic Amides with Maleimides

摘要

In the past two decades, transition-metal catalyzed C-H functionalizations have made notable progress. C-H alkylation with alkenes is one of the most effective and straightforward methods for introducing functionalized alkyl groups because of its atom economy. Chelation- assisted C-H functionalization using a directing group is the most reliable method for achieving high efficiency and high regioselectivity in such reactions. In the reaction of palladium- catalyzed C-H activation in aromatic substrates, most of the reactions were occurred on the ortho-C(sp2 )-H bond. Only few reports about high regioselective benzylic C(sp3 )-H arylation and fluorination were reported by Yu and other groups through utilizing transition-directing groups.