Transition metals and transition metals/lewis acid cooperative catalysis for directing group assisted para-CH functionalization

Abstract

In the past few decades, synthetic organic chemistry has been invigorated with the development of transition metal catalyzed directing group assisted regioselective CH functionalization. Although this approach started its journey with ortho-CH functionalization its steady advancement has succeeded in providing distal para-CH activation. All the challenges to reach distal para-CH bonds through the formation of a macrocyclic transition state are addressed by this strategy to a great extent. In a complementary approach, transition metal and Lewis acid cooperative catalysis were exploited to accomplish site-selective para-CH functionalization. In the last few years, these approaches delivered an ample number of reports which have emerged as an alternative to the traditional para-electrophilic/nucleophilic functionalizations of arenes. In this review, we compile those achievements to provide a quick overview in the field of directing group assisted para-selective CH functionalization.