Herein, we report that highly chemoselective and enantioselective reduction of 2-vinyl-substituted pyridines has been achieved for the first time. The reaction, which uses chiral spiro-bicyclic bisboranes as catalysts and HBpin and an acidic amide as reducing reagents, proceeds through a cascade process involving 1,4-hydroboration followed by transfer hydrogenation of a dihydropyridine intermediate. The retained double bond in the reduction products permits their conversion to natural products and other useful heterocyclic compounds by simple transformations.
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http://dx.doi.org/10.1002/anie.202007352 | DOI Listing |
RSC Adv
January 2025
School of Chemistry and Chemical Engineering, Shanxi University Taiyuan 030006 China
Ionic liquid (IL) units in heterogeneous catalysts exhibit synergistic effects to enhance catalytic performance and stabilize catalytically active centers, while also preventing the degradation of catalysts during the reaction process. Ionic liquid units in IL-functionalized CMOF catalysts enhance their catalytic performance in a synergistic manner. However, not only are the yields of IL-functionalized CMOFs obtained with post-synthesis methods low, but they also lead to blocking of the MOF pores and leaching of the ionic liquid.
View Article and Find Full Text PDFChem Rev
December 2024
University of Texas at Austin, Department of Chemistry, 105 E 24th St., Welch Hall (A5300), Austin, Texas 78712, United States.
Angew Chem Int Ed Engl
December 2024
Department of Applied Chemistry, Anhui Province Engineering Laboratory for Green Pesticide Development and Application, and Anhui Province Key Laboratory of Crop Integrated Pest Management, Anhui Agricultural University, Hefei, 230036, China.
An efficient enantioselective coupling reaction between sulfenamides and cyclic diaryliodonium salts is established via adaptive Cu/anionic stereogenic-at-Co(III) complex combined catalysis, precisely synthesizing a broad range of axially chiral sulfilimines with excellent enantioselectivities, diastereoselectivities, regioselectivities, and chemoselectivities (67 examples under same conditions, up to 98 % ee). The following thermodynamically controlled pyramidal inversion enables efficient stereodivegent synthesis of all four stereoisomers. Mechanistic studies suggest that anionic stereogenic-at-cobalt(III) complexes serve as counteranions of diaryliodonium and anionic ligand of Cu(I) catalyst simultaneously, which could be regarded as an explanation for outstanding selectivities.
View Article and Find Full Text PDFNat Chem
December 2024
Key Laboratory of Precision and Intelligent Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei, P. R. China.
Precisely differentiating chemicals featuring minor discrepancies is the prerequisite for achieving high selectivities in both chemical synthesis and biological activities. However, efficient strategies to differentiate and sort such congeneric compounds are lacking, posing daunting challenges for synthetic endeavours aimed at their orderly incorporation. Here we report a dynamic amine-sorting strategy that incorporates the chemoselective formation of the aminomethyl cyclopalladated complex to achieve the efficient differentiation of amine congeners.
View Article and Find Full Text PDFOrg Biomol Chem
December 2024
Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas 75390, USA.
We describe the development of a unified synthetic strategy for the preparation of all known 5/5-spirocyclic spiroindimicin (SPM) alkaloids, namely spiroindimicins B-G. The present synthetic route relies on four fundamental transformations: Grignard-based fragment coupling between halogenated pyrrolemetal and isatin partners, Suzuki coupling to generate a triaryl scaffold encompassing all requisite skeletal atoms of the natural products, Lewis acid-mediated spirocyclization to construct the 5/5-spirocyclic core, and chemoselective lactam reduction. The developed syntheses are step-economic (6-7 steps from commercial materials), scalable, and amenable to analogue synthesis.
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