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Potassium ferricyanide oxidation of salt 1 gave isoquinolinone 7 whose treatment with Grignard reagents resulted in a high-yield formation of substituted isoquinolinium salts 5. The selectivity of the reduction of these salts to give derivatives 6 has been studied. Particularly good selectivities (82-84%) were observed when R is a benzylic group. On the basis of these results, a practical and enantioselective synthesis of the natural alkaloid (-)-argemonine is presented.
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http://dx.doi.org/10.1021/jo0357869 | DOI Listing |
Chem Rec
September 2025
Department of Chemistry, St. Thomas College Palai, Arunapuram P.O., Kottayam, Kerala, 686574, India.
An α-aryl-substituted enantioenriched ketone is a valuable building block for the production of both natural and medicinal compounds. Research into their asymmetric synthesis can be challenging yet rewarding because of the need to control regio-, chemo-, and enantioselectivity carefully. A wide range of catalytic strategies has been developed during the past three decades to gain access to these favored motifs.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, Key Laboratory of Chemical Biology of Fujian Province, and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
The enantioselective construction of quaternary carbon stereocenters bearing amine functionalities represents a significant challenge in organic synthesis despite their prevalence in pharmaceutically active compounds. Herein, we report a versatile metallaphotoredox platform for the asymmetric incorporation of amine fragments onto quaternary carbons via coupling of alkene-tethered aryl bromides with readily available α-silylamines. This transformation proceeds under mild conditions without requiring organometallic reagents or stoichiometric reductants.
View Article and Find Full Text PDFChem Commun (Camb)
September 2025
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India.
A regio-, diastereo-, and enantioselective cobalt-catalyzed C-H activation/annulation of aromatic and alkenyl amides has been developed to access heterocycles featuring vicinal C-C and C-N diaxes. This strategy uniquely harnesses previously unexplored electronically unbiased internal alkynes and proceeds under mild conditions to deliver products in high yields with excellent regio- and stereocontrol.
View Article and Find Full Text PDFChem Sci
August 2025
Department of Organic Chemisty, Faculty of Science, Charles University Hlavova 2030/8 128 00 Prague 2 Czech Republic
Chiral saddle-shaped molecules are an emerging class of compounds with significant potential in both materials science and medicinal chemistry. However, their broader application has been hindered by limited synthetic accessibility. Herein, we report a metal-free, organocatalytic protocol for the oxidative lactonization of readily available aldehydic derivatives, enabling the efficient synthesis of chiral saddle-shaped lactones.
View Article and Find Full Text PDFChem Asian J
August 2025
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
Herein, we disclose a catalytic asymmetric Friedel-Crafts alkylation of N-aryl anilines with aurone-derived azadienes for the first synthesis of benzofuran and N-aryl aniline containing triarylmethanes. An easily available chiral phosphoric acid, TRIP, was found to be effective for this reaction. The triarylmethanes with benzofuran and N-aryl aniline motifs were obtained in moderate yields with high regio- and good to high enantioselectivities.
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