Recent advances in metal-free aerobic C–H activation

Abstract

An overview of recent reactions based on the metal-free, dioxygen-induced, C–H activation of various radical precursors.

New Dimensions in Rongalite Chemistry: The Land of Opportunities in Organic Synthesis and Material Sciences

“…Among the available methods for its synthesis, the most popular are Paal‐Knorr and Feist‐Benary furan synthesis. On the other hands, currently, the inert C−H bonds activation/functionalization for the construction of diverse heterocyclic scaffolds has also been the booming research area among the scientific community . To this context, in 2016, Wang et al .…”

Functionalisation of ethereal-based saturated heterocycles with concomitant aerobic C–H activation and C–C bond formation

“…[18][19][20][21] However, existing approaches, whilst effective, typically employ specialised initiators and/or careful management of reaction conditions to achieve this in a controlled fashion. [22][23][24][25][26] Aerobic C-H activation, utilising oxygen in air to promote radical-based C-H bond cleavage, represents a potentially ideal approach, [26][27][28][29][30] but to date has not been exploited for the formation of C-C bonds on saturated heterocycles. To explore this idea, we initially examined tetrahydrofuran (THF, 1a) as a candidate for aerobic C-H activation as THF derivatives are highly sought after.…”

Oxidase‐Type C−H/C−H Coupling Using an Isoquinoline‐Derived Organic Photocatalyst

“…Developments in transition metal‐catalyzed oxidase chemistry, particularly those based on Pd [1a, 2] and Cu, [2, 3] have resulted in a number of efficient aerobic C−H oxidation methods. Considering the cost, availability, and potential toxicity of many metal ions, however, metal‐free oxidase chemistry is an attractive alternative to its metal‐catalyzed counterpart [4] …”

“…[4] Organic photocatalysis [5] has emerged as a promising approach to move metal-free aerobic oxidation chemistry beyond simple auto-oxidation. [4] Nevertheless, reported examples mostly describe oxygenase-type activity (Figure 1a), where the oxygen atom(s) from O 2 is incorporated into the organic products. Oxidase-type activity is largely limited to oxidation of alcohols to aldehydes and oxidation amines to imines (Figure 1b).…”