Transformable/modifiable directing group-assisted C(sp2)–H functionalizations

Abstract

Directing groups have been widely used for transition metal-catalyzed regioselective C–H functionalizations. The heteroatoms in the directing group coordinate with the metal catalyst and activate relatively inert C–H bonds. However, after the desired C–H functionalization, the directing groups may not always be necessary, so their removal demands extra synthetic steps. This limitation can be overcome by employing a directing group that can be transformed into another valuable functionality in one pot or can be easily modified post C–H functionalization. In this review, we shall discuss the recent developments in such transformable/modifiable directing groups that afford complex organic scaffolds through C(sp²)–H activation-initiated one-pot and step-economical synthesis.