Transition-Metal-Catalyzed Site-Selective C–H Functionalization of Quinolines beyond C2 Selectivity

Abstract

Quinoline is an important scaffold in many natural products, biologically active compounds, and functional materials. The C-H functionalization of quinoline scaffolds by transition metal catalysis provided an efficient method for rapidly obtaining substituted quinolines. This review summarizes recently reported transition-metal-catalyzed site-selective C-H functionalization of quinolines, excluding C2 selective reactions. A review of direct functionalization of quinoline N-oxides at the C8 position also is provided.

Rhodium‐Catalyzed C(sp2)‐ or C(sp3)−H Bond Functionalization Assisted by Removable Directing Groups

“…[207][208][209][210] Thedirected C À H bond functionalization of heterocycles has also been extensively studied in attempts to overcome the issue of selectivity. TheC ÀHa ctivation of heterocycles can be mainly classified according to two approaches: i) nondirected and ii)directed functionalization.…”

Metal‐Free Remote C‐H Bond Acetoxylation of 8‐Aminoquinolines on the C5‐Position

“…In the last few years, extensive efforts have been devoted for the C‐H functionalization of quinoline motifs at the easily accessible C2, C3 and C8 positions. In contrast, selective remote C‐H functionalization of geometrically inaccessible C4 and C5 positions of quinoline skeletons gained particular attention only recently …”

Recent advances in the C–H-functionalization of the distal positions in pyridines and quinolines

“…1 However, with numerous C–H-bonds simultaneously available for activation, site-selective functionalization of complex molecules remains a significant challenge. 2 In pyridines, quinolines, and other structurally-related N -heterocycles, the C2 position can be readily functionalized using a variety of transition metal-catalyzed reactions with Pd, 3,4 Cu, 5 Ni, 6 Rh, 7 Ru, 8 Fe, 9 and Ag 10 as catalysts, as well as by means of non-catalytic approaches.…”