Direct cross-coupling between simple arenes and heterocyclic amines under mild conditions is undoubtedly important for C–N bonds construction. Selective C(sp2)-H amination is more valuable. Herein we show a selective C(sp2)-H amination of arenes (alkyl-substituted benzenes, biphenyl and anisole derivatives) accompanied by hydrogen evolution by using heterocyclic azoles as nitrogen sources. The reaction is selective for C(sp2)-H bonds, providing a mild route to N-arylazoles. The KIE (kinetic isotope effect) experiment reveals the cleavage of C–H bond is not involved in the rate-determining step. Kinetic studies indicate the first-order behaviour with respect to the arene component. It is interesting that this system works without the need for any sacrificial oxidant and is highly selective for C(sp2)-H activation, whereas C(sp3)-H bonds are unaffected. This study may have significant implications for the functionalization of methylarenes which are sensitive to oxidative conditions.

Oxidative C–H/N–H cross-coupling is one of the most atom-economical methods for the construction of C–N bonds. However, traditional oxidative C–H/N–H cross-coupling either required the use of strong oxidants or high reaction temperature, which makes it difficult to tolerate redox active functional groups. Herein we describe an external chemical oxidant-free electrooxidative C–H/N–H cross-coupling between electron-rich arenes and diarylamine derivatives. Under undivided electrolytic conditions, a series of triarylamine derivatives are produced from electron-rich arenes and diarylamine derivatives with high functional group tolerance. Both of the coupling partners are redox active in oxidative C–H/N–H cross-coupling, which enables high regioselectivity in C–N bond formation. Exclusive para-selectivity is observed for the coupling with anilines.

Considering the synthetic value of introducing active alcoholic hydroxyl group, developing C–H functionalization of alcohols is of significance. Herein, we present a photochemical method that under visible light irradiation, selectfluor can effectively promote the oxidative cross-coupling between alcohols and heteroarenes without the external photocatalysis, achieving the selective α sp3 C–H arylation of alcohol, even in the presence of ether. The N-F activation of selectfluor under blue LEDs irradiation is evidenced by electron paramagnetic resonance (EPR) study, which is the key process for the oxidative activation of α sp3 C–H alcohols. The observed reactivity may have significant implications for chemical transformations.

Benzo­[4,5]­imidazo­[2,1-a]­isoquinolin-6­(5H)-one derivatives are prevalent in many synthetic intermediates, pharmaceuticals, and organic materials. Herein, we develop a Mn-catalyzed electrochemical radical cascade cyclization reaction that uses electricity as the primary energy input to promote the reaction, leading to a series of benzo­[4,5]­imidazo­[2,1-a]­isoquinolin-6­(5H)-one derivatives under exogenous-oxidant-free conditions. It is worth noting that this electrochemical method can not only realize the synthesis of benzo­[4,5]­imidazo­[2,1-a]­isoquinolin-6­(5H)-one derivatives but also provides a new strategy for generating alkyl radicals from alkylboronic acids.

Considering the synthetic value of phosphonates, developing powerful catalytic methods for the phosphonylation of C­(sp2)–H bonds is important. Herein, we achieve a visible-light-induced external oxidant-free oxidative phosphonylation of C­(sp2)–H bonds via the combination of photocatalysis and proton-reduction catalysis. Mechanistic studies indicate that the visible-light-induced electron-rich arene radical cation is the key reactive intermediate. The synthetic application of this approach is demonstrated in the late-stage functionalization of pharmaceutical molecules. This study may have significant implications for the functionalization of C­(sp2)–H bonds, especially for those that are sensitive to oxidative conditions.