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A simple and efficient synthesis of cyclopenta[l]phenanthrenes from substituted acetophenones provides access to polycyclic aromatics with a variety of substitution patterns. The synthesis requires only three steps from a silyl enol ether: a Mukaiyama aldol reaction followed by McMurry coupling and then Mallory photocyclooxidation to give the target phenanthrenes. Photocyclization conditions have been found that give regioselective formation of 2,7-phenanthrenes from bis(meta-substituted) stilbenes.
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http://dx.doi.org/10.1021/acs.orglett.6b02008 | DOI Listing |
Org Lett
September 2025
Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gujarat 382355, India.
Herein, we report an easily tunable and regioselective Pd-catalyzed allene-alkyne coupling protocol for the stereodivergent synthesis of - and -1,3-enynes using purine allenamine by a simple switch of ligands P(-tolyl)Ph and Boc-Phe-OH. For the first time, we have explored mono--protected amino acids (MPAAs) as ligands in allene-alkyne coupling to furnish -1,3-enynes selectively. This protocol streamlined the access to chiral 1,3-enynes and addressed the long-standing stereoselectivity challenges associated with 1,3-enynes from allene-alkyne coupling.
View Article and Find Full Text PDFOrg Lett
September 2025
Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata-700009, India.
This study introduces microwave-assisted, Fe(III)-catalyzed ring-opening annulations of isoxazoles, enabling the rapid and selective synthesis of 1,4-diacyl pyrroles and substituted pyridines. By leveraging microwave irradiation and transition metal catalysis, this approach enhances the reaction efficiency, reduces reaction times, and promotes high regioselectivity under mild conditions. Under thermal conditions, the Ru(II) catalyst led to the synthesis of nicotinamide derivatives.
View Article and Find Full Text PDFNat Commun
September 2025
Department of Chemistry, Institute of Silicon Chemistry and Catalysis Research Center, TUM School of Natural Sciences, Technische Universität München, Garching bei München, Germany.
Catalytic reduction of quinolines has gained continuous interest in both academia and industry, providing direct and efficient access to tetrahydroquinolines or 1,2-dihydroquinolines. The catalytic preparation of tetrahydroquinolines has been extensively studied by transition metal complexes. By contrast, the related catalytic synthesis of 1,2-dihydroquinolines remains underdeveloped due to the difficulties in achieving precise control over both chemo- and regioselectivity.
View Article and Find Full Text PDFOrg Biomol Chem
September 2025
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28, bld. 1 Vavilova St, 119334 Moscow, Russian Federation.
4,4-Difluoro-4-bora-3,4-diaza--indacene systems (BODIPY) are widely investigated fluorophores. The BODIPY core allows for introducing substituents at different positions. Taking advantage of the versatile properties of carborane cages for the modification of photoactive compounds, we developed the synthesis of carborane-substituted BODIPYs.
View Article and Find Full Text PDFChem Sci
August 2025
College of Chemistry and Chemical Engineering, Jiangxi Province Engineering Research Center of Ecological Chemical Industry, Jiujiang University Jiujiang 332005 China
BN-fused aromatic compounds have garnered significant attention due to their unique electronic structures and exceptional photophysical properties, positioning them as highly promising candidates for applications in organic optoelectronics. However, the regioselective synthesis of BN isomers remains a formidable challenge, primarily stemming from the difficulty in precisely controlling reaction sites, limiting structural diversity and property tunability. Herein, we propose a regioselective synthetic strategy that employs 2,1-BN-naphthalene derivatives, wherein selective activation of N-H and C-H bonds is achieved in conjunction with -halogenated phenylboronic acids.
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