A metal- and reagent-free, electrochemical intramolecular oxidative amination reaction of tri- and tetrasubstituted alkenes has been developed. The electrosynthetic method proceeds through radical cyclization to form the key C-N bond, allowing a variety of hindered tri- and tetrasubstituted olefins to participate in the amination reaction. The result is the efficient synthesis of a host of alkene-bearing cyclic carbamates and ureas and lactams.
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http://dx.doi.org/10.1021/jacs.7b01016 | 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
IISER Kolkata: Indian Institute of Science Education and Research Kolkata, Department of Chemical Sciences, Mohanpur, 741246, Nadia, INDIA.
Chiral allyl amines are important structural components in natural products, pharmaceuticals, and chiral catalysts. Herein, we report a cobalt-catalyzed enantioselective reductive coupling of imines with internal alkynes to synthesize chiral allyl amines. The reaction is catalyzed by a cobalt complex derived from commercially available bisphosphine ligand utilizing zinc as the electron donor.
View Article and Find Full Text PDFOrg Lett
January 2025
College of Advanced Interdisciplinary Science and Technology (CAIST), Henan University of Technology, Zhengzhou 450001, Henan, P. R. China.
We present an iron-photocatalyzed decarboxylative alkylation strategy involving carboxylic acids and Morita-Baylis-Hillman (MBH) acetates to synthesize -type tri- and tetrasubstituted alkenes with moderate to excellent stereoselectivity (/ ratio up to >19:1). This method is applicable to a broad range of structurally diverse primary, secondary, and tertiary alkyl carboxylic acids, as well as complex pharmaceutical and natural carboxylic acids, achieving efficient alkylation of various MBH acetates under mild conditions (>60 examples, with yields up to 96%). This approach offers a powerful strategy for streamlined alkylation.
View Article and Find Full Text PDFOrg Lett
December 2024
Guangxi Key Laboratory of Electrochemical and Magneto-Chemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China.
Rh(III)-catalyzed dual N-H and triple C-H activation/(4 + 2) annulation of 2-aryl-2,3-dihydro-1-perimidines and alkynes has been disclosed to construct 4,5,14,15-tetrasubstituted cationic azaperylenes with high yields (up to 95%) and broad scope. Tandem (4 + 2) annulation of 1-perimidines with vinylene carbonate and alkynes affords 4,5-disubstituted azaperylene salts, and -alkynyl 1-perimidines undergo an intra- and intermolecular annulation cascade to give 4,5,14-trisubstituted targets. Most of the intermediates were detected by ESI-MS, indicating a convincible mechanism including three possible paths.
View Article and Find Full Text PDFChem Sci
August 2024
Department of Chemistry, University of York Heslington York YO10 5DD UK
Here, we analyze the stereodynamic properties of bullvalenes using principal moments of inertia and exit vector plots to draw comparisons with commonly used ring systems in medicinal chemistry. To aid analyses, we first classify (i) the four elementary rearrangement steps available to substituted bullvalenes, which (ii) can be described by applying positional descriptors (α, β, γ, and δ) to the substituents. We also (iii) derive an intuitive equation to calculate the number of isomers for a given bullvalene system.
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