DFT computations have been executed aimed at illuminating the variety of pathways by which pyridones react with alkynes in the presence of [CpCoL(2)]: NH-2-pyridones furnish N-dienylated ligands (N-H activation pathway), N-methyl-2-pyridones are converted into ligated cyclohexadienes ([2+2+2] cocycloaddition pathway), and N-alkynyl-2-pyridones may undergo either [2+2+2] cocycloaddition or C-dienylation (C-H activation), depending on the length of the tether. The calculations predict the formation of the experimentally observed products, including their regio- and stereochemical make up. In addition, the unusual regiochemical outcome of the all-intramolecular [2+2+2] cycloaddition of N,N'-dipentynylpyrazinedione was rationalized by computation, which led to the discovery of a new mechanism.
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http://dx.doi.org/10.1002/chem.200601822 | DOI Listing |
Org Lett
January 2025
China Guangxi Key Laboratory of Pharmaceutical Precision Detection and Screening, Guangxi Key Laboratory of Bioactive Molecules Research and Evaluation, and Key Laboratory of Micro-Nanoscale Bioanalysis and Drug Screening of Guangxi Education Department, Pharmaceutical College, Guangxi Medical University, Nanning 530021, China.
Herein, a one-pot domino catalyzed three-component process is described, which is initiated by a palladium/zinc cooperatively catalyzed cycloaddition between trimethylenemethane (TMM) and unactivated alkyl/aryl imines, followed by one-pot isomerization and Zn(OTf)-catalyzed DDQ oxidation, furnishing valuable substituted pyrroles. We disclose that the palladium/zinc cooperative catalysis affords a dual-Zn(OTf)-stabilized azapalladacycle, wherein the Pd-N bond is polarized by Zn(OTf), facilitating a unique outer-sphere allylic amination. Moreover, subsequent DDQ dehydrogenation can be feasibly promoted by zinc catalysis.
View Article and Find Full Text PDFChem Sci
December 2024
Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford South Parks Road Oxford OX1 3QR UK
The reaction chemistry of an unprecedented 'inorganic cumulene' - featuring a five-atom BNBNB chain - towards C[double bond, length as m-dash]O (and related) multiple bonds is disclosed. In marked contrast to related all-carbon systems, the intrinsic polarity of the BNBNB chain (featuring electron-rich nitrogen and electron-deficient boron centres) enables metathesis chemistry with electrophilic heteroallenes such as CO and with organic carbonyl compounds. Transfer of the borylimide unit to [CO], [CS], [PP{(NDippCH)}] and [C(H)Ph] moieties generates (boryl)N[double bond, length as m-dash]C[double bond, length as m-dash]X systems (X = O, S, PP{(NDippCH)}, C(H)Ph), driven thermodynamically by B-O bond formation.
View Article and Find Full Text PDFChem Sci
November 2024
Molecular Inorganic Chemistry and Catalysis, Inorganic and Structural Chemistry, Center for Molecular Materials, Faculty of Chemistry, Universität Bielefeld Universitätsstrasse 25 D-33615 Bielefeld Germany http://www.ghadwalgroup.de.
The first carbocyclic gallylene [(ADC)Ga(GaI)] and bis-gallylene [(ADC)Ga] (ADC = PhC{N(Dipp)C}; Dipp = 2,6-iPrCH) featuring a central CGa ring annulated between two 1,3-imidazole rings are prepared by KC reductions of [(ADC)GaI]. Treatment of [(ADC)Ga] with Fe(CO) affords complex [(ADC)GaFe(CO)] in which each Ga(i) atom serves as a two-electron donor. [(ADC)Ga] activates white phosphorus (P) and the C -F bond of aryl fluorides (ArF) to yield compounds [(ADC)Ga(P)] and -/-[(ADC)GaF(Ar)], respectively.
View Article and Find Full Text PDFChem Biodivers
January 2025
Matrusri Education Society, Department of Sciences and Humanities, Matrusri Engineering College, Hyderabad, 500059, Hyderabad, INDIA.
In this work, we have adopted an easy route to synthesizing bis-1,2,3-triazole-based benzophenone compounds via a 1,3-dipolar cycloaddition reaction (Click Chemistry). All the target compounds achieved better yields though the microwave-assisted method than the conventional method. Target compounds structure were confirmed based on the IR, 1H NMR, 13C NMR and HR Mass analysis.
View Article and Find Full Text PDFNat Commun
January 2025
Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, Chemical Biology Research Center, School of Pharmaceutical Sciences, Chongqing University, Chongqing, China.
Helicene-shaped molecules are compelling chemical structures with unique twisted helical chirality and remarkable properties. Although progress occurs in the catalytic asymmetric synthesis of helicene (-like) molecules, the enantioselective synthesis of multiple helicenes, especially four or higher helicity, is still challenging and has yet to be achieved. Herein, we report an organocatalytic [4 + 2] cycloadditions to achieve double S-shaped quadruple helicene-like molecules with high enantioselectivity (up to 96% e.
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