Pd-Catalyzed Regioselective Halogenation of Arenes

Significance

This work describes a novel catalytic method for the regioselective halogenation of a variety of substituted arenes, bearing an ortho-directing group. Chlorination, bromination and iodination of arenes is possible, using 5 mol% of Pd(OAc)₂ as a catalyst and readily available N-halosuccinimides as halogenating agents. A large number of directing groups are suitable for the reaction. This method is often complementary to the usual electrophilic halogenation, and allows a straightforward preparation of various aryl halides, which are otherwise difficult to achieve.