Heterocycles are widely present in natural products, pharmaceuticals, and organic functional materials. In heterocycle synthesis, Pd-catalyzed cascade C–H functionalization has been regarded as one of the most powerful approaches due to its advantages in terms of high atom efficiency and readily available starting materials. In this review, we will briefly introduce the major advances in palladium-catalyzed cascade C(sp³)–H activation and annulation for constructing different types of heterocycles through inter- and intramolecular pathways from 2010 to 2023.

2-Pyridone ligand-facilitated palladium-catalyzed direct C–H bond functionalization via the transient directing group strategy has become an attractive topic. Here, we report a Pd-catalyzed direct β-C(sp³)–H arylation reaction of tertiary aliphatic aldehydes by using an α-amino acid as a transient directing group in combination with a 2-pyridone ligand.

2-Pyridone ligand-facilitated palladium-catalyzed direct C–H bond functionalization via the transient directing group strategy has become an attractive topic. Here we report a Pd-catalyzed direct β-C(sp3) –H arylation reaction of tertiary aliphatic aldehydes by using an α-amino acid as a transient directing group in combination with a 2-pyridone ligand.