Recent Advances in Aerobic Oxidative of C−H Bond by Molecular Oxygen Focus on Heterocycles

Abstract

Aerobic oxidative cross‐coupling represents one of the most straightforward and atom‐economic methods for construction of C−C and C−X (X=N, O, S, or P) bonds using air as a sustainable external oxidant. The oxidative coupling of C−H bonds in heterocyclic compounds can effectively increase their molecular complexity by introducing new functional groups through C−H bond activation, or by formation of new heterocyclic structures through cascade construction of two or more sequential chemical bonds. This is very useful as it can increase the potential applications of these structures in natural products, pharmaceuticals, agricultural chemicals, and functional materials. This is a representative overview of recent progress since 2010 on green oxidative coupling reactions of C−H bond using O2 or air as internal oxidant focus on Heterocycles. It aims to provide a platform for expanding the scope and utility of air as green oxidant, together with a brief discussion on research into the mechanisms behind it.

Iron-catalyzed selective construction of indole derivatives via oxidative C(sp3)–H functionalization of indolin-2-ones

“…1–11 Inspired by iron-containing enzyme catalysis, 12,13 the iron-catalyzed C(sp 3 )–H bond oxidation, coupled with the utilization of molecular oxygen, has emerged as a highly promising reaction over the past decade. 14–24 In 2015, Li's group pioneered the utilization of cross-dehydrogenative coupling (CDC) to develop an iron salt-catalyzed cross-dehydrogenative arylation between 3-substituted indolin-2-ones generating a series of 3,3′-disubstituted oxindole compounds. 25 Subsequently, Xu's group achieved significant progress by expanding the scope of the iron-catalyzed CDC reaction to include indolin-2-ones and various X–H bonds (X = C, N, or S), enabling the construction of functionalized indole derivatives by employing air as the sole oxidant (Scheme 1(I)).…”