In the last decade numerous techniques have been developed in Pd-catalysed distal C–H activation ranging from template-assisted to the use of inherent functional groups as the directing auxiliary including ligand-enabled transformations.
Distal meta-selective C–H olefination, allylation, acetoxylation and cyanation of α-substituted cinnamates have been reported. New coupling partners such as quinones, maleimides and sulfolene were utilized for the first time in meta-C–H activation.
Polyfunctionalized β-ketone sulfones are prepared in one-pot through a series of processes including radical relay, radical addition, hydrogen abstraction, hydrolysis or oxidation.
Macrocyclization via palladium-catalyzed intramolecular meta-selective C–H olefination was achieved through utilizing a readily accessible and cleavable indolyl template.