Novel Reactions of [60]Fullerene with Amino Acid Esters and Carbon Disulfide

Multicomponent Reaction of CS2, Amines, and Sulfoxonium Ylides in Water: Straightforward Access to β-Keto Dithiocarbamates, Thiazolidine-2-thiones, and Thiazole-2-thiones

Simple, versatile, and catalyst-free synthetic methods for β-keto dithiocarbamates, thiazolidine-2-thiones, and thiazole-2-thiones via the multicomponent reaction of CS₂, amines, and sulfoxonium ylides have been described. The β-keto sulfoxonium ylides furnished β-keto dithiocarbamates in the presence of CS₂ and secondary amines, whereas primary amines afforded thiazolidine-2-thiones or thiazole-2-thiones after dehydration in an acidic environment. With simple procedures, the reaction has a wide substrate scope and excellent functional group tolerance.

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.

Copper-Catalyzed Aerobic Oxidative Reaction of C60 with Aliphatic Primary Amines and CS2

A novel type of fullerene derivatives, [60]fullerothiazolidinethiones (2), were obtained from the copper-catalyzed aerobic oxidative reaction of C₆₀ with aliphatic primary amines and CS₂ in 4:1 v/v DMF and o-DCB. The obtained products were fully characterized with the X-ray single-crystal diffraction and spectroscopic methods. Control experiment with maleic anhydride, an analogue to C₆₀, also afforded thiazolidinethione product, but via a mechanism different from that of C₆₀ judging from the structure difference between the two types of thiazolidinethione compounds, demonstrating the unique reactivity of C₆₀.

On the Reaction Mechanism of the Rhodium-Catalyzed Arylation of Fullerene (C60) with Organoboron Compounds in the Presence of Water

Density functional theory (DFT) calculations were carried out to study the reaction mechanism of the Suzuki-Miyaura rhodium-catalyzed hydroarylation of fullerene (C60) by phenylboronic acid in the presence of water. As found experimentally, our results confirm that addition of the phenyl group and the hydrogen atom in C60 occurs at the [6,6] bond. The rate-determining step corresponds to the simultaneous transfer of a hydrogen atom from a water molecule to C60 and the recovery of the active species. The use of 2-phenyl-1,3,2-dioxaborinane and the 4,4,5,5-tetramethyl-2-phenyl-1,3,2,-dioxaborolane instead of phenylboronic acid as organoborate agents does not lead to great modifications of the energy profile. The possible higher steric hindrance of 4,4,5,5-tetramethyl-2-phenyl-1,3,2,-dioxaborolane should not inhibit its use in the hydroarylation of C60. Overall, we show how organoboron species arylate C60 in rhodium-based catalysis assisted by water as a source of protons.

Peptide Bond Formation in Water Mediated by Carbon Disulfide

Demonstrating plausible nonenzymatic polymerization mechanisms for prebiotic monomers represents a fundamental goal in prebiotic chemistry. While a great deal is now known about the potentially prebiotic synthesis of amino acids, our understanding of abiogenic polymerization processes to form polypeptides is less well developed. Here, we show that carbon disulfide (CS2), a component of volcanic emission and sulfide mineral weathering, and a widely used synthetic reagent and solvent, promotes peptide bond formation in modest yields (up to ∼20%) from α-amino acids under mild aqueous conditions. Exposure of a variety of α-amino acids to CS2 initially yields aminoacyl dithiocarbamates, which in turn generate reactive 2-thiono-5-oxazolidone intermediates, the thio analogues of N-carboxyanhydrides. Along with peptides, thiourea and thiohydantoin species are produced. Amino acid stereochemistry was preserved in the formation of peptides. Our findings reveal that CS2 could contribute to peptide bond formation, and possibly other condensation reactions, in abiogenic settings.

[60]Fullerenyl amino acids and peptides: a review of their synthesis and applications

This review reports on the latest progress in the synthesis of fullerenyl amino acids and related derivatives, and categorises the molecules into functional types for different uses: these include directly attached fullerenyl amino acids, fullerenyl N- and C-capping amino acids, and those amino acids in which the [60]fullerene group is attached to the amino acid side chain.

A simple and straightforward synthesis of phenyl isothiocyanates, symmetrical and unsymmetrical thioureas under ball milling

Anilines were efficiently transformed into isothiocyanates (5.0 equiv. CS₂) or thioureas (1.0 equiv. CS₂) under ball milling and promoted by KOH.

Selective introduction of organic groups to C60 and C70 using organoboron compounds and rhodium catalyst: a new synthetic approach to organo(hydro)fullerenes

A Rh-catalyzed reaction of C(60) and C(70) with organoboron compounds is described. This new catalytic method enables introduction of various organic groups onto C(60) and C(70). [Rh(cod)(MeCN)(2)]BF(4) proved to be the most effective catalyst in terms of productivity and selectivity. The reaction generally proceeds with a high regioselectivity and in a mono-addition selective manner. It was found that water is an essential additive to promote the reaction. By X-ray crystal structure analysis, we have confirmed the reaction site of organometallic-based hydroarylation of C(70) for the first time. Various functional fullerenes, such as fullerene-tagged amino acids and fullerene-capped π systems, can be synthesized. The X-ray crystal structure of biphenyl-attached C(60) revealed an interesting opportunity for the well-organized alignment of bucky balls by taking advantage of CH-π interactions.

Controlled regio- and chemoselective addition of isothiocyanate to the dione moiety of a cage-opened fullerene-mixed peroxide derivative

Addition of the ambident SCN group to a fullerendione derivative follows two different pathways in the presence and absence of Lewis acid.

Reactivity of fullerene epoxide: preparation of fullerene-fused thiirane, tetrahydrothiazolidin-2-one, and 1,3-dioxolane

The epoxide moiety in the fullerene-mixed peroxide C60(O)(OOtBu)4 1 reacts readily with aryl isocyanates ArNCS (Ar = Ph, Naph) to form both the thiirane derivative C60(S)(OOtBu)4 and fullerene-fused tetrahydrothiazolidin-2-one. The reaction of 1 with trimethylsilyl isothiocyanate TMSNCS yields the isothiocyanate derivative C60(NCS)(OH)(OOtBu)4, the isothiocyanate and hydroxyl moieties of which could be converted to a fullerene-fused tetrahydrothiazolidin-2-one ring with alumina quantitatively. Treating 1 with BF3.Et2O yields the fullerene-fused [1,3,2]-dioxoborolane derivative C60(O2BOH)(OOtBu)4. In the presence of aldehyde or acetone, BF3.Et2O catalyzes the conversion of epoxide to fullerene-fused 1,3-dioxolane derivatives. The products are characterized by spectroscopic data. Two of the compounds are also characterized by single-crystal X-ray analysis.

Unexpected reactions of [60]fullerene involving tertiary amines and insight into the reaction mechanisms

Thermal reactions of [60]fullerene with amino acid ester hydrochlorides and triethylamine in o-dichlorobenzene at reflux afforded pyrrolidinofullerene derivatives containing the CH(3)CH moiety and originating from triethylamine through an unusual C-N bond cleavage. Detailed investigation of these thermal reactions resulted in the discovery of unprecedented reactions between C(60) and tertiary amines and of reactions of C(60) with tertiary amines and aldehydes, giving cyclopentafullerene derivatives with high stereoselectivity. Plausible reaction mechanisms for the product formation involving the uncommon C-N bond cleavage of tertiary amines were proposed on the basis of extensive experimental results.

Novel multicomponent reaction of [60]fullerene: the first example of 1,4-dipolar cycloaddition reaction in fullerene chemistry

The novel multicomponent reaction of [60]fullerene with dimethyl acetylenedicarboxylate and isoquinoline, quinoline or substituted quinolines was investigated. This type of reaction presents the first example of a 1,4-dipolar cycloaddition reaction in fullerene chemistry.