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On-surface synthesis involving the homocoupling of aryl-alkynes affords the buildup of bisacetylene derivatives directly at surfaces, which in turn may be further used as ingredients for the production of novel functional materials. Generally, homocoupling of terminal alkynes takes place by thermal activation of molecular precursors on metal surfaces. However, the interaction of alkynes with surface metal atoms often induces unwanted reaction pathways when thermal energy is provided to the system. In this contribution we report about light-induced metal-free homocoupling of terminal alkynes on highly oriented pyrolitic graphite (HOPG). The reaction occurred with high efficiency and selectivity within a self-assembled monolayer (SAM) of aryl-alkynes and led to the generation of large domains of ordered butadiynyl derivatives. Such a photochemical uncatalyzed pathway represents an original approach in the field of topological C-C coupling at the solid/liquid interface.
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http://dx.doi.org/10.1021/jacs.6b03589 | DOI Listing |
Angew Chem Int Ed Engl
September 2025
Shenzhen Grubbs Institute, Department of Chemistry, Guangming Advanced Research Institute, and Shenzhen Key Laboratory of Cross-Coupling Reactions, Southern University of Science and Technology, Shenzhen, 518055, China.
Despite the widespread utility of transition metal-catalyzed cross-couplings in organic synthesis, the coupling of unactivated alkyl electrophiles remains challenging due to sluggish oxidative addition and competing side reactions. Here, we describe a general and practical copper-catalyzed radical deoxyalkynylation of α-unfunctionalized alcohols through a synergistic combination of Barton-McCombie deoxygenation and copper-catalyzed radical cross-coupling. Key to the success of this method lies in not only the development of rigid anionic multiple N,N,N-ligand to exert remarkable selectivity of highly reactive unactivated alkyl radicals, but also the selection of one suitable oxidant to suppress Glaser homocoupling and other side products.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada.
We report the thermal and photoactivation of a solution-stable Mn nitride ligand radical complex , which facilitates N-N bond homocoupling to generate N, a reaction commonly observed in Mn nitrides. Theoretical calculations suggest that the nitride is ambiphilic, facilitating the N-N bond formation. Notably, photoactivation of the Mn ligand radical at room temperature enables rapid C-H bond activation, leading to the formation of C-N insertion products, excluding dihydroanthracene where a desaturation product is observed.
View Article and Find Full Text PDFJ Org Chem
August 2025
Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721-302, India.
The tandem intramolecular hydroamination-Povarov-type reaction of 1,4-aminoalkynes at 50 or 75 °C gave the spiro-dipyrroloquinolines () in 61-91% yields. When the temperature of the reaction was increased to 110 or 135 °C, yet another homocoupled monopyrroloquinoline () was isolated in 24-86% yields along with as a minor product. From the reaction of the terminal 1,3-aminoalkyne in methanol at 110 °C, one of the diastereomers of an octahydro-dipyrroloquinoline was isolated as a solid in a 48% yield.
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.
Perchlorate, initially regarded as a weakly coordinating counterion rather than a reactive oxidizing reagent due to its kinetic stability, has garnered attention for its potential in microbial systems. Under anaerobic conditions, microbes utilize perchlorate as a terminal oxidant for methane oxidation, involving two distinct stages: extraction and release of oxidizing ability. This two-phase activation process necessitates the collaborative action of multiple enzymes, a phenomenon not extensively explored in artificial systems.
View Article and Find Full Text PDFDalton Trans
November 2024
Institute for Inorganic Chemistry, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
The carbene-stabilised beryllium Grignards [(CAAC)BeBrR] (R = CAACH 1a, Dur 1b; CAAC/H = 1-(2,6-dipropylphenyl)-2,2,4,4-tetramethylpyrrolidin-2-yl/idene; Dur = 2,3,5,6-tetramethylphenyl) undergo salt metathesis with various pseudohalide salt precursors. Whereas with [NaNCS] the thiocyanato Grignards [(CAAC)Be(NCS)R] (R = CAACH 2a, Dur 2b) are obtained selectively, salt metatheses with [Na(OCP)(dioxane)] and [K(OCN)] are fraught with side reactions, in particular scrambling of both neutral and anionic ligands, leading to complex product mixtures, from which the first examples of beryllium phosphaethynolate Grignards [(thf)(CAACH)Be(OCP)] (3) and [(CAAC)Be(OCP)R] (R = CAACH 4a, Dur 4b), as well as the isocyanate-bridged hexamer [(CAAC)BrBe(1,3-μ-OCN)] (7) were determined as the main products. The complexity of possible side reactions is seen in complex 5, a byproduct of the salt metathesis of 1b with [Na(OCP)(dioxane)], which hints at radical redox processes, OCP homocoupling, OCP coupling with CAAC, as well as OCP insertion into the Be-R bond.
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