This study analyzes the feasibility of utilizing the catalytic and enantioselective [4 + 2] cycloaddition of sterically demanding heterocycle-incorporated siloxydienes to yield polycyclic skeletons with a tetrasubstituted carbon. A catalyst derived from lanthanide triflimide enabled the reaction. The mechanistic investigations and transformations of the adducts are also discussed. The proposed approach facilitates the synthesis of intricate polysubstituted skeletons, each with multiple contiguous chiral centers, thereby aiding in the production of diverse hydrocarbazoles for drug discovery purposes.
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http://dx.doi.org/10.1021/acs.joc.4c00837 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Jain University - Ramanagara Campus, Centre for Nano and Material Sciences, Jakkasandra Post Kanakapura Taluk, Ramanagara-562112, Bangalore, 562112, Bangalore, INDIA.
The development of a metallic copper-based catalyst system remains a significant challenge. Herein, we report the synthesis of highly stable, active, and reusable Cu0 catalyst for the carboboration of alkynes using carbon electrophiles and bis(pinacolato)diboron (B2pin2) as chemical feedstocks to afford di- and trisubstituted vinylboronate esters in a regio- and stereoselective manner with appreciable turnover number (TON) of up to 2535 under mild reaction conditions. This three-component coupling reaction works well with a variety of substituted electrophiles and alkynes with broad functional group tolerance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, 100084, China.
Enantioselective hydrogenation of tetrasubstituted alkenes to form 1,2-contiguous stereocenters is a particularly appealing but highly challenging transformation in asymmetric catalysis. Despite the notable progress achieved in enantioselective hydrogenation over the past decades, enantioselective hydrogenation of all-carbon tetrasubstituted alkenes containing multiple alkyl groups remains an unsolved challenge. Here, we report a rhodium-catalyzed highly diastereo- and enantioselective hydrogenation of diverse acyclic multisubstituted alkenes under mild conditions.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Univ Rennes, CNRS, ISCR - UMR 6226, F-35000 Rennes, France.
A straightforward and highly diastereoselective synthesis of -4-hydroxypiperidines is presented. This method allows access to C2 and C4 substituted piperidines, bearing a tetrasubstituted carbon stereocenter at C4. -Disubstituted homoallylic amines and ketoaldehydes as carbonyl partners have been rarely used in aza-Prins cyclizations, expanding the scope of this reaction.
View Article and Find Full Text PDFJ Org Chem
January 2025
National Engineering Research Center of Pesticide, College of Chemistry, Nankai University, Tianjin 300071, China.
This study introduces a novel methodology for the direct construction of tetrasubstituted centers, utilizing secondary C(sp)-H and C(sp)-H substrates, specifically indolin-2-ones and indoles, through an innovative oxidative cross-coupling reaction. Facilitated by a straightforward copper salt catalyst, this reaction proceeds efficiently at a mild temperature of 40 °C under operationally streamlined conditions. Emphasizing sustainability, this method is notably enhanced by employing air (molecular oxygen) as an eco-friendly oxidant.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Chemistry, College of Sciences, Tianjin University of Science and Technology, Tianjin 300457, People's Republic of China.
A sequential [3 + 2]/[2 + 1] annulation reactions of benzimidazole- and indole-derived acrylonitriles with vinylsulfonium salts have been developed for the first time, and shown to provide in yields of 32 to 98% a series of azabicyclo[3.1.0]hexanes containing each a cyano-substituted tetrasubstituted carbon stereocenter with >20 : 1 dr.
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