The first highly enantioselective asymmetric Friedel-Crafts reaction/cyclization reaction of 5-aminopyrazoles with 3-alkenyloxindoles to afford polycyclic heterocyclic compounds bearing an all-carbon quaternary stereocenter catalyzed by a complex of Ni with the -symmetric bipyridine-,'-dioxide ligand has been developed. The relevant products with a wide range of substrates and good functional tolerance were obtained in 89-98% yield with 56-99% ee in the presence of 10 mol % Ni(OTf) and 11 mol % in DCM at 25 °C. Moreover, an experiment on scaling up the process along with the transformations of the cycloadducts further emphasized the practical application of the synthesis.
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http://dx.doi.org/10.1021/acs.orglett.4c03674 | DOI Listing |
Acc Chem Res
January 2025
Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States.
ConspectusThe manipulation of strained rings is a powerful strategy for accessing the valuable chemical frameworks present in natural products and active pharmaceutical ingredients. Aziridines, the smallest N-containing heterocycles, have long served as building blocks for constructing more complex amine-containing scaffolds. Traditionally, the reactivity of typical aziridines has been focused on ring-opening by nucleophiles or the formation of 1,3-dipoles.
View Article and Find Full Text PDFChemphyschem
January 2025
The University of Sheffield, school of mathematical and physical sciences, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Pentalene (C8H6) and NN- and BB-bridged heterocyclic analogues (BN)4H6, derived by replacement of CC pairs with BN, are taken as paradigms for tuning of ring-current (anti)aromaticity by variation of π charge, electronegativity and substitution pattern. Ab initio calculation of maps for the π current density induced in these model systems by a perpendicular external magnetic field exhibits the full range of tropicity, from diatropic aromatic to nonaromatic to paratropic antiaromatic, with a ready rationalisation in terms of an orbital model. Further calculations on systems of varying charge in which these motifs are embedded in extended PAH systems with naphthalene and phenanthrene 'clamps' show promise for switching between current patterns and related opto-electronic properties.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong, 528200, P. R. China.
B- and N-heterocyclic fluorophores have reveal promising efficiency in blue organic light-emitting diodes (OLEDs) with small full-width-at-half-maximum (FWHM). However, their structural determinants for spectral broadening and operating stability are still needed to be investigated in further. Herein, a novel multi-N-heterocycles Diindolo[3,2,1jk:3',2',1'jk]dicarbazole[1,2-b:4,5-b] (DIDCz) is proposed to manipulate the emission color toward pure blue region by extending π-conjugation of the N-π-N bridge.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Postovsky Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, S. Kovalevskoy Street, 22, Ekaterinburg 620137, Russia.
The synthetic approach based on a sequence of Buchwald-Hartwig cross-coupling and annulation through intramolecular oxidative cyclodehydrogenation has been used for the construction of novel 4-alkyl-4-thieno[2',3':4,5]pyrrolo[2,3-]quinoxaline derivatives. For the first time, these polycyclic compounds were evaluated for antimycobacterial activity, including extensively drug-resistant strains. A reasonable bacteriostatic effect against HRv was demonstrated.
View Article and Find Full Text PDFJ Org Chem
January 2025
College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000, People's Republic of China.
A copper-catalyzed domino addition/cyclization reaction was developed to synthesize novel benzoselenazole-linked 1,2,3-triazole and tetracyclic fused 12-benzo[4,5]selenazole[2,3-]quinazolin-12-one derivatives from isoselenocyanates. This domino reaction efficiently constructed multiple new chemical bonds in a single step, forming either four (one C-Se and three C-) or three (one C-Se and two C-) bonds. The reaction offers several key advantages, including mild conditions, broad substrate compatibility, and straightforward and safe operation.
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