We describe a metal-free strategy to access various α-arylidene cyclopenta[]indoles phosphine-catalysed (3 + 2) annulation of α,β-ynones and 3-nitroindoles. For the first time, the rearomatisation of the indole nucleus was observed in such an annulative transformation. The method was extended to the synthesis of an antimalarial natural product, bruceolline E.
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http://dx.doi.org/10.1039/d2ob02180c | DOI Listing |
ACS Cent Sci
January 2025
Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
Recently, nickel catalysts have garnered considerable attention for their efficacy and versatility in asymmetric catalysis, attributed to their distinctive properties. However, the use of cost-effective and sustainable divalent nickel catalysts in C-H activation/asymmetric alkene insertion poses significant challenges due to the intricate control of stereochemistry in the transformation of the tetracoordinate C-Ni(II) intermediate. Herein, we report a Ni(II)-catalyzed enantioselective C-H/N-H annulation with oxabicyclic alkenes.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Science, China Pharmaceutical University, Nanjing 210009, P. R. China.
An -heterocyclic carbene-catalyzed atroposelective [3 + 3] annulation of alkynyl acylazoliums with benzothiazole derivatives has been developed for the divergent synthesis of axially chiral triaryl 2-pyranones and fused 2-pyridones. The regioselectivity of this protocol depends on the structure of benzothiazoles with three different nucleophilic centers. The obtained axially chiral frameworks represent a new class of arylheterocycle atropisomers, which may be potentially useful in medicinal chemistry.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, Chongqing, 400715, China.
A copper-catalyzed [4 + 2] annulation protocol from readily available α,β-unsaturated ketoximes and dialkyl acetylenedicarboxylates has been achieved. The approach enables the expedient construction of a series of structurally new highly substituted pyridines with good functional group tolerance.
View Article and Find Full Text PDFChem Sci
January 2025
Institute of Chemistry, Academia Sinica 128 Academia Road, Section 2, Nankang Taipei 115201 Taiwan
Nanographenes and polycyclic aromatic hydrocarbons exhibit many intriguing physical properties and have potential applications across a range of scientific fields, including electronics, catalysis, and biomedicine. To accelerate the development of such applications, efficient and reliable methods for accessing functionalized analogs are required. Herein, we report the efficient synthesis of functionalized small nanographenes from readily available iodobiaryl and diarylacetylene derivatives a one-pot, multi-annulation sequence catalyzed by a single palladium catalyst.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Chemistry and Chemical Engineering, Key Laboratory of Functional Molecular Engineering of Guangdong Province, South China University of Technology, Guangzhou 510640, China.
The chemoselective defluorinative [3 + 3] annulation of (trifluoromethyl)alkenes with thioureas is reported. This protocol affords various attractive 6-fluoro-3,4-dihydropyrimidine-2(1)-thiones in high yields, features transition-metal free, mild conditions, efficient, is operationally simple and gram-scalable, tolerates diverse useful functional groups.
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