One-Pot Sequential Synthesis of Acetoxylated [60]Fullerene Derivatives

Palladium-catalyzed three-component 1,4-aminoarylation of [60]fullerene with aryl iodides and N-methoxysulfonamides, and further transformations

The palladium-catalyzed three-component 1,4-aminoarylation of [60]fullerene afforded 1,4-(aryl)(sulfonamide)[60]fullerenes, of which the sulfonamide group could be replaced by a (hetero)aryl, malonate ester or allyl group in the presence of FeCl3.

H2O2-mediated room temperature synthesis of 2-arylacetophenones from arylhydrazines and vinyl azides in water

An environmentally benign, cost-efficient and practical methodology for the room temperature synthesis of 2-arylacetophenones in water has been discovered. The facile and efficient transformation involves the oxidative radical addition of arylhydrazines with α-aryl vinyl azides in the presence of H₂O₂ (as a radical initiator) and PEG-800 (as a phase-transfer catalyst). From the viewpoint of green chemistry and organic synthesis, the present protocol is of great significance because of using cheap, non-toxic and readily available starting materials and reagents as well as amenability to gram-scale synthesis, which provides an attractive strategy to access 2-arylacetophenones.

Cu(I)-Catalyzed Synthesis of [60]Fullerene-Fused Lactams and Further Electrochemical Functionalization

A novel and efficient Cu(I)-catalyzed radical heteroannulation reaction of [60]fullerene (C₆₀) with α-bromo acetamides has been disclosed for the direct synthesis of diverse C₆₀-fused lactams. Furthermore, the formed C₆₀-fused lactams can be served as a versatile platform for further electrochemical functionalization to prepare 1,2-, 1,4-, 1,2,3,16-, and 1,4,9,25-adducts of C₆₀. In addition, a representative fullerene product has been applied as an overcoating layer of the electron-transporting layer in n-type perovskite solar cell.

A copper-promoted synthesis of epoxy-bridged [60]fullerene-fused lactones and further derivatization

A facile copper-promoted decarboxylative annulation of [60]fullerene (C60) with two identical α-oxocarboxylic acids via an unprecedented cascade addition pathway has been exploited to synthesize the unique epoxy-bridged C60-fused lactones for the first time. Further transformations into the rare epoxy-bridged C60-fused hemiacetals and bicyclic-fused 1,2,3,4-adducts as well as application in a perovskite solar cell device of the obtained products have also been demonstrated. The structures of the epoxy-bridged C60-fused lactones and derived reductive products have been unequivocally established by single-crystal X-ray crystallography. Plausible reaction mechanisms leading to the observed products are proposed.

Potassium salt promoted regioselective three-component coupling synthesis of 1,4-asymmetrical [60]fullerene bisadducts with superior electron transport properties

An efficient one-pot three-component domino coupling reaction of phenols, C₆₀, and bromoalkanes was developed, resulting in the highly regioselective synthesis of 1,4-asymmetrical C₆₀ bisadducts.

Manganese(iii) acetate-mediated activation of C–H bonds of weak CH-acids; addition ofo-carborane, its derivatives, and some other CH-acids to [60]-fullerene

CH-acids includingo-carboranes add to C₆₀by a carbon atomviaoxidative-ion-transfer reactions mediated by Mn(OAc)₃.

Synthesis of fullerotetrahydropyridazines via the copper-catalyzed heteroannulation of [60]fullerene with hydrazides

Fullerotetrahydropyridazines have been efficiently synthesized via the copper-catalyzed reaction of [60]fullerene with hydrazides.

Simple and Efficient Generation of Aryl Radicals from Aryl Triflates: Synthesis of Aryl Boronates and Aryl Iodides at Room Temperature

Despite the wide use of aryl radicals in organic synthesis, current methods to prepare them from aryl halides, carboxylic acids, boronic acids, and diazonium salts suffer from limitations. Aryl triflates, easily obtained from phenols, are promising aryl radical progenitors but remain elusive in this regard. Inspired by the single electron transfer process for aryl halides to access aryl radicals, we developed a simple and efficient protocol to convert aryl triflates to aryl radicals. Our success lies in exploiting sodium iodide as the soft electron donor assisted by light. This strategy enables the scalable synthesis of two types of important organic molecules, i.e., aryl boronates and aryl iodides, in good to high yields, with broad functional group compatibility in a transition-metal-free manner at room temperature. This protocol is anticipated to find potential applications in other aryl-radical-involved reactions by using aryl triflates as aryl radical precursors.

Covalent functionalization of polyhedral graphitic particles synthesized by arc discharge from graphite

Occurrence of covalent functionalization of astralenes by radical addition.

Regioselective C-3 arylation of coumarins with arylhydrazines via radical oxidation by potassium permanganate

An efficient protocol for oxidative C-3 arylation of coumarins with arylhydrazine has been developed using potassium permanganate as an oxidant. The arylated coumarins with different electronic properties were obtained in moderate to good yields. The developed protocol for direct C-3 arylation of coumarins could be extended to quinolinones.

Ferric perchlorate-mediated one-step reaction of [60]fullerene with primary amides for the synthesis of fullerooxazoles

The reaction of [60]fullerene with amides promoted by cheap and easily available ferric perchlorate affords a series of interesting fullerooxazole derivatives.

Palladium-catalyzed aerobic oxidative cross-coupling of arylhydrazines with terminal alkynes

The Pd-catalyzed aerobic oxidative coupling of arylhydrazines with terminal acetylenes was achieved under copper- and base-free conditions.

Copper(i)-catalyzed heteroannulation of [60]fullerene with ketoxime acetates: preparation of novel 1-fulleropyrrolines

A cuprous bromide-catalyzed heteroannulation reaction of [60]fullerene with ketoxime acetates has been exploited to prepare novel 1-fulleropyrrolines via N–O bond cleavage and C–C/C–N formation under thermal conditions.

Ni-Catalyzed direct 1,4-difunctionalization of [60]fullerene with benzyl bromides

A new Ni-catalyzed direct 1,4-difunctionalization of [60]fullerene with various benzyl bromides has been developed, leading to the 1,4-bisadducts in good to high yields and high 1,4-selectivities.

NBS-promoted oxidation of fullerene monoradicals leading to regioselective 1,4-difunctional fullerenes

We have demonstrated that NBS is able to promote the oxidation of fullerene monoradicals to form 1,4-difunctional fullerenes. The singly bonded fullerene dimers were used as fullerene monoradical precursors, which produced various 1,4-fullerenes with a wide range of functional groups in good to high yields with high regioselectivity in terms of cosolvents and nucleophiles.

The trapping of phenyldiazenes in cycloaddition reactions

The reactivity of phenyldiazenes was studied intensively in the late 1960s, but not much is known about their behavior under acidic conditions. Based on the formation of phenyldiazenes from phenylazocarboxylates, we herein describe how reactions of phenyldiazenes can be directed into ionic or radical pathways. Cycloaddition reactions with furans leading to pyridazinium salts represent the first examples for the direct trapping of phenyldiazenes with conservation of the N=N moiety.

Synthetic applications of arylboronic acid via an aryl radical transfer pathway

The transition-metal-catalyzed functionalization of arylboronic acids is the most powerful tool for the formation of carbon-carbon and carbon-heteroatom bonds in modern organic synthesis. These transformations are generally considered to proceed via organometallic intermediates generated by transmetalation from the boronic acids. Interestingly, there is a novel recognition that arylboronic acids can serve as aryl radical precursors via oxidative carbon-boron bond cleavage in recent years. Manganese(III) acetate, Ag(I)/persulfate and iron(II or III)/persulfate catalytic systems have been shown to be effective for this transformation. In this review, recent advances in this new area are highlighted and their mechanisms are also discussed.

Manganese(IV)-mediated hydroperoxyarylation of alkenes with aryl hydrazines and dioxygen from air

We report a new carbooxygenation-type version of the Meerwein arylation in which the introduction of oxygen is achieved by using dioxygen from the air. In this way, hydroperoxides were obtained from activated as well as non-activated alkenes by oxidizing aryl hydrazines with manganese dioxide. The best results were obtained with α-substituted acrylates. Importantly, the aryl hydrazine has to be added slowly to the reaction mixture to allow sufficient uptake of dioxygen from the air. Competition and labeling experiments revealed hydroperoxyl radicals as novel oxygen-centered radical scavengers.

Synthesis of oxazolidinofullerenes/thiazolidinofullerenes: novel reaction of [60]fullerene with isocyanates/isothiocyanates promoted by ferric perchlorate

The facile one-step reaction of [60]fullerene with isocyanates/isothiocyanates in the presence of ferric perchlorate generates a series of novel oxazolidinofullerenes/thiazolidinofullerenes.

Mechanochemistry of fullerenes and related materials

The low or lack of solubility of fullerenes, carbon nanotubes and graphene/graphite in organic solvents and water severely hampers the study of their chemical functionalizations and practical applications. Covalent and noncovalent functionalizations of fullerenes and related materials via mechanochemistry seem appealing to tackle these problems. In this review article, we provide a comprehensive coverage on the mechanochemical reactions of fullerenes, carbon nanotubes and graphite, including dimerizations and trimerizations, nucleophilic additions, 1,3-dipolar cycloadditions, Diels-Alder reactions, [2 + 1] cycloadditions of carbenes and nitrenes, radical additions, oxidations, etc. It is intriguing to find that some reactions of fullerenes can only proceed under solvent-free conditions or undergo different reaction pathways from those of the liquid-phase counterparts to generate completely different products. We also present the application of the mechanical milling technique to complex formation, nanocomposite formation and enhanced hydrogen storage of carbon-related materials.

Chemistry of fullerene epoxides: synthesis, structure, and nucleophilic substitution-addition reactivity

Fullerene epoxides, C₆₀O_n, having epoxide groups directly attached to the fullerene cage, constitute an interesting class of fullerene derivatives. In particular, the chemical transformations of fullerene epoxides are expected to play an important role in the development of functionalized fullerenes. This is because such transformations can readily afford a variety of mono- or polyfunctionalized fullerene derivatives while conserving the epoxy ring arrangement on the fullerene surface, as seen in representative regioisomeric fullerene polyepoxides. The first part of this review addresses the synthesis and structural characterization of fullerene epoxides. The formation of fullerene epoxides through different oxidation reactions is then explored. Adequate characterization of the isolated fullerene epoxides was achieved by concerted use of NMR and LC-MS techniques. The second part of this review addresses the substitution of fullerene epoxides in the presence of a Lewis acid catalyst. Most major substitution products have been isolated as pure compounds and their structures established through spectroscopic methods. The correlation between the structure of the substitution product and the oxygenation pattern of the starting materials allows elucidation of the mechanistic features of this transformation. This approach promises to lead to rigorous regioselective production of various fullerene derivatives for a wide range of applications.