Tongxin Liu

Synthesis of [60]fullerene-fused tetrahydroazepinones and azepinonimines via Cu(OAc)2-promoted N-heteroannulation reaction.

A convenient and efficient Cu(OAc)2-mediated N-heteroannulation reaction of [60]fullerene with N-sulfonylated o-amino-aromatic methyl ketones or O-alkyl oximes has been reported for the synthesis of novel and scarce [60]fullerene-fused tetrahydroazepinones and -azepinonimines in a highly selective manner. Moreover, a possible mechanism involving two pathways is proposed on the basis of the experimental observations.

Dimethyl sulfoxide participant iron-mediated cascade oxidation/α-formylation reaction of substituted 2,3-dihydropyrroles under air and protonic acid free condition.

An efficient and Brønsted acid free one-pot protocol to directly generate structurally sophisticated α-formylpyrrole derivatives in moderate to good yields has been demonstrated, involving an iron-mediated domino oxidation/formylation reaction of readily available 2,3-dihydro-1H-pyrroles in dimethyl sulfoxide and air atmosphere, in which dimethyl sulfoxide acts as the formyl donor. A possible mechanism is presented.

Synthesis of multisubstituted pyrroles from doubly activated cyclopropanes using an iron-mediated oxidation domino reaction.

An alternative route has been developed for the construction of multisubstituted pyrrole derivatives from readily available, doubly activated cyclopropanes and anilines using an iron-mediated oxidation domino reaction (i.e., sequential ring-opening, cyclization, and dehydrogenation reactions). This reaction uses readily available reactants and is tolerant of a broad range of substrates, with the desired products being formed in good to excellent yields.

Iron-catalyzed vinylogous aldol condensation of Biginelli products and its application toward pyrido[4,3-d]pyrimidinones.

A novel iron-catalyzed vinylogous aldol condensation of Biginelli products with aryl aldehydes has been developed for the syntheses of potential bioactive (E)-6-arylvinyl-dihydropyrimidin-2(1H)-ones. These materials are valuable synthetic precursors to drug-like pyrido[4,3-d]pyrimidine derivatives. The amide group at the 5-position of the dihydropyrimidin-2(1H)-ones played an important role in the vinylogous aldol condensation reaction.

Iron-Catalyzed Intramolecular C(sp(2))-N Cyclization of 1-(N-Arylpyrrol-2-yl)ethanone O-Acetyl Oximes toward Pyrrolo[1,2-a]quinoxaline Derivatives

An efficient and convenient iron-catalyzed protocol has been developed for the synthesis of substituted pyrrolo[1,2-a]quinoxalines from 1-(N-arylpyrrol-2-yl)ethanone O-acetyl oximes through N-O bond cleavage and intramolecular directed C-H arylation reactions in acetic acid.

Iron-mediated internal-oxidant relay cascade reaction: strategy to synthesize fullerenooxazoles and hydroxyfullerenyl amides.

A novel FeCl2·4H2O-mediated internal-oxidant relay cascade reaction has been developed by functionalization of O-substituted benzohydroxamic acids or N-chloro-arylamides with [60]fullerene. Depending on the nature of the N-substituted groups, fullerenooxazoles or rare hydroxyfullerenyl amides could be obtained in a straightforward and flexible manner. Such a new transformation provides a unique strategy for the synthesis of fullerenooxazoles or hydroxyfullerenyl amides.

PIFA-Mediated oxidative cyclization of 1-aroyl-N-arylcyclopropane-1-carboxamides and their application in the synthesis of pyrrolo[3,2-c]quinolinones

An efficient ring-closing reaction was developed for the synthesis of spirocyclopropane quinolinediones from 2,2-disubstituted 2-benzoylacetamides in the presence of [bis-(trifluoroacetoxy)iodo]benzene (PIFA). This reaction proceeds at room temperature in the absence of a metal catalyst to provide spirocyclopropane quinolinediones in good to excellent yields. Furthermore, these compounds were readily converted to the corresponding pyrrolo[3,2-c]quinolinones to provide tricyclic ring structures similar to those found in the natural products martinellic acid and martinelline via an intermolecular amine ring-opening cyclization reaction.

Copper(I) catalyzed C(sp2)–N bond formation: synthesis of pyrrolo[3,2-c]quinolinone derivatives

An intramolecular copper-catalyzed direct C(sp2)–H activation/C(sp2)–N bond formation reaction has been developed for the synthesis of pyrrolo[3,2-c]quinolinone derivatives under an oxygen atmosphere.

Synthesis of C60-Fused Tetrahydrocarbazole/Dibenzothiophene/Benzothiophene and Dibenzofuran Derivatives via Metal-Free Oxidative Dehydrogenative Carboannulation

A transition-metal-free oxidative dehydrogenative coupling reaction has been developed for the direct construction of novel C60-fused tetrahydrocarbazoles, dibenzothiophenes, benzothiophenes, and dibenzofurans. This new carboannulation reaction features high atom economy, operational simplicity, broad substrate scope, and excellent functional-group tolerance and provides a convenient access to a scarce class of fullerene derivatives.

Oxidation of β-Ketoamides: The Synthesis of Vicinal Tricarbonyl Amides

A facile and direct oxidative reaction for the synthesis of vicinal tricarbonyl amides in moderate to excellent yields (53-88%) was developed starting from readily available β-ketoamides in the presence of phenyliodine(III) bis(trifluoroacetate). The resulting products possess significant synthetic potential, making this approach a valuable addition to the group of traditional methods already available for the preparation of these molecules.