Herein we describe the first use of disubstituted donors in the palladium-catalyzed trimethylenemethane (TMM) cycloaddition resulting in an enantioselective synthesis of highly substituted pyrrolidines. These cyanoalkyl donors 1 form all-carbon quaternary centers in a catalytic, asymmetric, and intermolecular manner uniquely using diamidophosphite ligands L2 and L3, generating synthetically important chiral building blocks in good yields and selectivities.
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http://dx.doi.org/10.1021/ja312351s | DOI Listing |
J Am Chem Soc
January 2025
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
Despite tremendous progress of dienamine catalysis along with its application in enantioselective synthesis over nearly two decades, certain limitations, especially with respect to the regioselectivity in the dienamine generation step, continue to persist. To overcome these shortcomings of classical dienamine catalysis, we now introduce the concept of alkoxy-directed dienamine catalysis and apply it to the enantioselective arene construction by desymmetrizing -enediones through [4 + 2]-cycloaddition. Catalyzed by a diphenylprolinol silyl ether, this reaction utilizes γ-alkoxy α,β-unsaturated aldehydes as the substrate and proceeds in a highly regioselective fashion through the intermediacy of δ-alkoxy dienamine.
View Article and Find Full Text PDFMolecules
January 2025
Department of Pharmacy, Jilin Medical University, Jilin 132013, China.
An efficient stereoselective synthesis of 10-hydroxy-10-(1-indol-3-yl)-9-(10)-phenanthrene derivatives was realized through an organocatalyzed Friedel-Crafts reaction of phenanthrenequinones and indoles using a (,)-dimethylaminocyclohexyl-squaramide as the catalyst. Under the optimized conditions, the desired chiral products were obtained in good yields (73-90%) with moderate to high ee values (up to 97% ee). Two pairs of synthesized enantiomers were subjected to evaluation of their antiproliferative activities on four types of human cancer cell lines and one human umbilical vein endothelial cell line using the CCK-8 assay.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Zhejiang Uiversity, Chemistry, 866 Yuhangtang Road, 310058, Hangzhou, CHINA.
Heck silylation of unactivated alkenes is an efficient strategy for the synthesis of useful organosilicon compounds. However, extensive efforts have been dedicated to only achieving achiral molecules. Herein, a highly regio- and enantioselective cobalt-catalyzed Heck silylation of unactivated alkenes with hydrosilanes is reported for the first time, providing access to axially chiral alkenes in good to excellent yields with 87-98% ee.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
The University of Manchester, School of Chemistry & Manchester Institute of Biotechnology, 131 Princess Street, M1 7DN, Manchester, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Amide bond formation is fundamental in nature and is widely used in the synthesis of pharmaceuticals and other valuable products. Current methods for amide synthesis are often step and atom inefficient, requiring the use of protecting groups, deleterious reagents and organic solvents that create significant waste. The development of cleaner and more efficient catalytic methods for amide synthesis remains an urgent unmet need.
View Article and Find Full Text PDFChem Rev
January 2025
Department of Chemistry, Northeast Normal University, Changchun 130024, China.
-Sulfonyl hydrazones have been extensively used as operationally safe carbene precursors in modern organic synthesis due to their ready availability, facile functionalization, and environmental benignity. Over the past two decades, there has been tremendous progress in the carbene chemistry of -sulfonyl hydrazones in the presence of transition metal catalysts, under metal-free conditions, or using photocatalysts under photoirradiation conditions. Many carbene transfer reactions of -sulfonyl hydrazones are unique and cannot be achieved by any alternative methods.
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