Transition-Metal-Catalyzed Directed C8–H Carbon–Carbon Bond Formation in Quinolines and 1,2,3,4-Tetrahydroquinolines

Abstract C8-Substituted quinoline (QN) and 1,2,3,4-tetrahydroquinoline (THQ) scaffolds are featured in numerous bioactive compounds and natural products. Appreciable efforts have been made towards the development of elegant techniques to functionalize the C8–H bond of QNs and THQs. The transition-metal-catalyzed chelation-assisted C–H activation strategy has emerged as an effective synthetic tool among existing methods. This review focuses on recent advances in transition-metal-catalyzed directed carbon–carbon bond forming reactions for the C8–H functionalization of QNs and THQs (till February 2023). The discussion has been categorized based on the type of reaction. 1 Introduction 2 Acylation 3 Alkylation 4 Alkenylation 5 Alkynylation 6 Allylation 7 Annulation 8 Arylation 9 Conclusion and Outlook