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.