Methods for direct C(sp 2 )-H bonds azidation.

Direct functionalization of C-H bonds has attracted great attention in recent years from the perspectives of atom and step economy. In this context, a variety of processes have been developed for the construction of synthetically and biologically important organic azides through the oxidative C-H bonds azidation. In this review, we have summarized recent progress in the direct azidation of C(sp 2 )-H bonds. The review is divided into three major sections: (i) direct azidation of aromatic C-H bonds; (ii) direct azidation of olefinic C-H bonds; and (iii) direct azidation of aldehydic C-H bonds. Mechanistic aspects of the reactions are considered and discussed in detail.