Rhodium(III)-Catalyzed C-H Activation of Arenes Using a Versatile and Removable Triazene Directing Group

摘要

In the past decade, transition-metal-catalyzed arene C-H bond functionalization reactions have enjoyed tremendous advances owing to their widespread applications to the rapid assembly of diversified complex molecular structures, particularly in the fields of medicinal chemistry and material sciences. Direct C-H activation and functionalization has advantages over classical cross coupling reactions based on aryl halides, The direct method bypasses the need for preactivated reaction partners (such as halides), and leads to a more atom-economical process. In these reactions, a directing group combined with a proper transition metal and a terminal oxidant is often required to achieve C-H chemo-selectivity and catalytic turnover. The directing groups, possessing functional groups containing a metal-binding heteroatom, can either undergo further cyclizations to form heterocycles or remain part of the products (Scheme 1).