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.
Macrocyclization via palladium-catalyzed intramolecular meta-selective C–H olefination was achieved through utilizing a readily accessible and cleavable indolyl template.
Highly meta-selective C–H olefination, deuteration and acetoxylation of benzyl alcohols were realized by applying a practical directing template featuring a non-aromatic cyclopentenyl-pyridine scaffold.
The selective functionalization of C−H bonds in arenes remains a challenging task in organic synthesis.
In this review, we have showcased the diverse aspects of transition-metal catalysis, biocatalysis, and photocatalytic C(sp3)–H bond functionalization to access lactones and lactams.