Nitrile as a Versatile Directing Group for C(sp²)–H Functionalizations

The one‐step direct regioselective functionaliztion of inert C( sp 2 )–H bonds is an efficient and sustainable methodology for the synthesis of a variety of useful natural products and pharmaceutical intermediates. A range of functional groups have been widely used as directing group for various regioselective transformations. Among these, the weakly coordinating nitrile group has attracted much attention because it is a transformable, easily installed and readily removed directing group, which can be easily converted into a number of different functional groups, such as carboxyl, carbamoyl, aminomethyl, carbonyl, and heterocyclic functionalities. This review describes recent advances in nitrile‐directed C–H functionalizations catalyzed by palladium(II), ruthenium(II), rhodium(III) and iridium(I) catalysts. The review is divided into sections related to ortho ‐, meta ‐, and para ‐C–H bond functionalizations, which are subdivided according to reaction type (olefination, arylation, halogenation, hydroxylation and acetoxylation). magnified image