A microwave-assisted regioselective reaction dealing with arylglyoxal monohydrate, diverse N-aryl enaminones, and indoles to achieve 3,2'- and 3,3'-bis-indoles by varying a substituted indole substrate is reported. The 2-unsubstituted indoles resulted in the 3,2'-bis-indole skeleton, whereas indoles bearing a methyl or phenyl group at C2 led to the 3,3'-bis-indoles with simultaneous formation of three sigma-bonds. The procedures feature excellent regioselectivity, short reaction times, convenient one-pot manner, and operational simplicity.
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http://dx.doi.org/10.1021/co3001428 | 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 PDFOrg Lett
December 2024
Hubei Key Laboratory of Natural Products Research and Development, College of Biological and Pharmaceutical Sciences, China Three Gorges University, Yichang, Hubei 443002, China.
An unexpected phosphine-catalyzed controllable three-component domino reaction involving [1 + 2 + 2] annulation and [1 + 2 + 2]/[3 + 2] sequential annulation reaction of 2-arylmethylidene cyanoacetates/malononitriles with Morita-Baylis-Hillman (MBH) carbonates has been developed. A broad range of densely functionalized cyclopentanes and diquinanes bearing five or four consecutive stereogenic centers, including two all-carbon quaternary stereocenters, were smoothly acquired in moderate to excellent yields under mild reaction conditions from readily available materials. Moreover, this divergent transformation enables the simultaneous generation of three or four new C-C bonds and one or two carbocyclic rings in only one step.
View Article and Find Full Text PDFChem Commun (Camb)
October 2024
Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM), Dhanbad, Jharkhand 826004, India.
An expedient route to 2-aminodihydrothiophenes and their seleno analogues is reported. A three-component photoredox reaction between alkene, thio(seleno)cyanate, and bromomalonate is employed, generating a carbo-thio(seleno)cyanate intermediate that undergoes a domino of reactions mediated by alumina column chromatography, leading to valuable chalcogen pharmacophores. Mechanistic investigations using DFT and control experiments reveals an intramolecular H-bond responsible for driving the domino forward.
View Article and Find Full Text PDFOrg Lett
October 2024
School of Chemistry and Molecular Engineering, Nanjing Tech University, 30 South Puzhu Road, Nanjing 211816, P. R. China.
An enantioselective 1,2-dicarbofunctionalization of vinyl (hetero)arenes with alkyl bromides and aryl bromides through nickel/photoredox catalysis is described. This three-component enantioselective domino alkyl arylation of vinyl (hetero)arenes could generate a diverse array of enantioenriched 1,1-diaryl(heteroaryl)alkanes with good to excellent yields (up to 88%) and high enantioselectivities (up to 99% ). This transformation could proceed well under mild conditions with excellent chemo- and regioselectivity due to the avoidance of the use of air- and moisture-sensitive organometallic reagents and stoichiometric metal reductants.
View Article and Find Full Text PDFOrg Biomol Chem
October 2024
School of Applied Material Sciences, Central University of Gujarat, Sector-30, Gandhinagar-382030, India.
A visible-light-induced C(sp)-H functionalization of indoles by using Schreiner's thiourea as the organocatalyst has been reported. With the aid of a three-component domino reaction between 2-hydroxybenzaldehydes, cyclic-1,3-diketones, and a variety of indoles, the corresponding densely functionalized xanthene scaffolds were isolated in good to excellent yields. Apart from these, a broad range of other bioactive natural products including kojic acid, lawsone, and 4-hydroxycoumarin were also investigated instead of indoles for the present work.
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