Nana Ma

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.

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.

Hypervalent Iodine(III)-Promoted Phenyl Transfer Reaction from Phenyl Hydrazides to Nitriles

A useful transformation of nitriles to N-phenyl amides has been achieved through a novel intermolecular phenyl transfer reaction from phenyl hydrazides and N-addition to nitriles in the presence of PIFA under mild and solvent-free conditions. This cross-coupling reaction includes the oxidative cleavage of sp2 C-N bonds of phenyl hydrazides to form a phenyl radical and the subsequent N-addition to cyanos to form new sp2 C-N bonds and provides efficient access to various N-phenyl amides in moderate to good yields under mild reaction conditions.

In Situ Generated TEMPO Oxoammonium Salt Mediated Tandem Cyclization of β-Oxoamides with Amine Hydrochlorides for the Synthesis of Pyrrolin-4-ones

A novel in situ generated TEMPO oxoammonium salt mediated one-pot tandem reaction has been developed for the straightforward construction of pyrrolin-4-ones from readily available β-oxoamides with amine hydrochlorides. The reaction tolerates various functional groups and represents a reliable method for the synthesis of highly substituted pyrrolin-4-ones in good yields under mild conditions. Detailed mechanistic studies disclosed that TEMPO oxoammonium salt generated in situ was crucial for the transformation involving the formation of enaminone precursors in situ by condensation of the β-oxoamides with amines, followed by sequential oxidative coupling with β-oxoamides, intramolecular cyclization, and 1,2-alkyl migration steps.

Broad Synthesis of Disubstituted Dihydrofuran-Fused [60]Fullerene Derivatives via Cu(I)/Ag(I)-Mediated Synergistic Annulation Reaction

A novel and efficient Cu(I)/Ag(I)-mediated synergistic annulation reaction of [60]fullerene with diarylethanones, benzoylacetonitriles, and β-dicarbonyl compounds has been developed for the direct construction of diverse disubstituted dihydrofuran-fused [60]fullerene derivatives. This transformation exhibits a remarkably broad substrate scope and functional group tolerance and provides a useful method to a scarce class of fullerene derivatives.

Experimental and computational investigations on the high binding-selectivity of pyrimidine derivatives by a pillar[5]arene

ABSTRACT The binding selectivity of an adenine-monofunctionalized pillar[5]arene (H) with a series of pyrimidine derivatives were investigated through 1H NMR experiments and density functional theory (DFT) study. High binding-selectivity was demonstrated. Typically, H displayed very strong binding strength with 6-(2,4-dioxo-3, 4-dihydropyrimidin-1 (2H)-yl)hexanenitrile (G1) [Ka >105 M−1], up to about 3000-fold as compared with 1-hexylpyrimidine-2,4(1H, 3H)-dione (G5) [Ka = 31 M−1]. The strong binding ability of H with G1 was due to the cooperative multiple hydrogen bond, dipole-dipole, C-H···π and π···π interactions. The high binding-selectivity was also verified by calculation results. The calculated interaction energy (ΔEi) of G1⊂H was −12.92 Kcal·mol−1 while that of G5⊂H was −2.85 Kcal·mol−1. Graphical Abstract

Syntheses of Acridones via Copper(II)-Mediated Relay Reactions from o-Aminoacetophenones and Arylboronic Acids

The reaction of o-aminoacetophenones and arylboronic acids catalyzed by copper(II) salts in the presence of pyridine under an O2 atmosphere provides a general and efficient one-pot preparation of biologically interesting acridones. This relay reaction comprises an intermolecular Suzuki cross-coupling, intramolecular oxidative C(sp3)-H amination, and C(sp2)-H activation with simultaneous rearrangement of the generated isatin intermediates. This strategy tolerates both electron-donating and -withdrawing functionalities to afford various acridones in good to excellent yields.