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1. Cobalt−NHC Catalyzed C(sp ² )−C(sp ³ ) and C(sp ² )−C(sp ² ) Kumada Cross‐Coupling of Aryl Tosylates with Alkyl and Aryl Grignard Reagents

   https://doi.org/10.1002/cctc.202001347  

   Piontek, Aleksandra; Ochędzan‐Siodłak, Wioletta; Bisz, Elwira; Szostak, Michal (November 2020, ChemCatChem)

   Abstract The first cobalt‐catalyzed cross‐coupling of aryl tosylates with alkyl and aryl Grignard reagents is reported. The catalytic system uses CoF₃and NHCs (NHC=N‐heterocyclic carbene) as ancillary ligands. The reaction proceeds via highly selective C−O bond functionalization, leading to the corresponding products in up to 98 % yield. The employment of alkyl Grignard reagents allows to achieve a rare C(sp²)−C(sp³) cross‐coupling of C−O electrophiles, circumventing isomerization and β‐hydride elimination problems. The use of aryl Grignards leads to the formation of biaryls. The C−O cross‐coupling sets the stage for a sequential cross‐coupling by exploiting the orthogonal selectivity of the catalytic system. 

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2. Carbodicarbene‐Stibenium Ion‐Mediated Functionalization of C(sp ³ )−H and C(sp)−H Bonds

   https://doi.org/10.1002/anie.202415070  

   Warring, Levi; Westendorff, Karl_S; Bennett, Marc_T; Nam, Kijeong; Stewart, Brennan_M; Dickie, Diane_A; Paolucci, Christopher; Gunnoe, T_Brent; Gilliard, Jr., Robert_J (November 2024, Angewandte Chemie International Edition)

   Abstract Main‐group element‐mediated C−H activation remains experimentally challenging and the development of clear concepts and design principles has been limited by the increased reactivity of relevant complexes, especially for the heavier elements. Herein, we report that the stibenium ion [(^pyCDC)Sb][NTf₂]₃(1) (^pyCDC=bis‐pyridyl carbodicarbene; NTf₂=bis(trifluoromethanesulfonyl)imide) reacts with acetonitrile in the presence of the base 2,6‐di‐tert‐butylpyridine to enable C(sp³)−H bond breaking to generate the stiba‐methylene nitrile complex [(^pyCDC)Sb(CH₂CN)][NTf₂]₂(2). Kinetic analyses were performed to elucidate the rate dependence for all the substrates involved in the reaction. Computational studies suggest that C−H activation proceeds via a mechanism in which acetonitrile first coordinates to the Sb center through the nitrogen atom in a κ¹fashion, thereby weakening the C−H bond which can then be deprotonated by base in solution. Further, we show that1reacts with terminal alkynes in the presence of 2,6‐di‐tert‐butylpyridine to enable C(sp)−H bond breaking to form stiba‐alkynyl adducts of the type [(^pyCDC)Sb(CCR)][NTf₂]₂(3 a–f). Compound1shows excellent specificity for the activation of the terminal C(sp)−H bond even across alkynes with diverse functionality. The resulting stiba‐methylene nitrile and stiba‐alkynyl adducts react with elemental iodine (I₂) to produce iodoacetonitrile and iodoalkynes, while regenerating an Sb trication. 

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3. Photoredox catalyzed C(sp3) C(sp) coupling of dihydropyridines and alkynylbenziodoxolones

   https://doi.org/10.1016/j.tetlet.2019.151230  

   Liang, Shengzong; Angnes, Ricardo A.; Potnis, Chinmay S.; Hammond, Gerald B. (November 2019, Tetrahedron Letters)
4. Phosphine-Directed sp ³ C–H, C–O, and C–N Borylation

   https://doi.org/10.1021/acs.joc.0c01706  

   Morris, Kelsey C.; Wright, Shawn E.; Meyer, Gillian F.; Clark, Timothy B. (November 2020, The Journal of Organic Chemistry)

   null (Ed.)
5. Two new endophytic species enrich the Coniochaeta endophytica / C. prunicola clade: Coniochaeta lutea sp. nov. and C. palaoa sp. nov.

   https://doi.org/doi.org/10.35535/pfsyst-2021-0006  

   Arnold, A.E. (January 2021, Plant and Fungal Systematics)

   null (Ed.)

   Coniochaeta (Coniochaetaceae, Ascomycota) is a diverse genus that includes a striking richness of undescribed species with endophytic lifestyles, especially in temperate and boreal plants and lichens. These endophytes frequently represent undescribed species that can clarify evolutionary relationships and trait evolution within clades of previously classified fungi. Here we extend the geographic, taxonomic, and host sampling presented in a previous analysis of the clade containing Coniochaeta endophytica, a recently described species occurring as an endophyte from North America; and C. prunicola, associated with necroses of stonefruit trees in South Africa. Our multi-locus analysis and examination of metadata for endophyte strains housed in the Robert L. Gilbertson Mycological Herbarium at the University of Arizona (ARIZ) (1) expands the geographic range of C. endophytica across a wider range of the USA than recognized previously; (2) shows that the ex-type of C. prunicola (CBS 120875) forms a well-supported clade with endophytes of native hosts in North Carolina and Michigan, USA; (3) reveals that the ex-paratype for C. prunicola (CBS 121445) forms a distinct clade with endophytes from North Carolina and Russia, is distinct morphologically from the other taxa considered here, and is described herein as Coniochaeta lutea; and (4) describes a new species, Coniochaeta palaoa, here identified as an endophyte of multiple plant lineages in the highlands and piedmont of North Carolina. Separation of CBS 120875 and CBS 121445 into C. prunicola sensu stricto and C. lutea is consistent with previously described genomic differences between these isolates, and morphological and functional differences among the four species (C. endophytica, C. prunicola, C. palaoa, and C. lutea) underscore the phylogenetic relationships described here. The resolving power of particular loci and the emerging perspective on the host- and geographic range of Coniochaeta and the C. endophytica / C. prunicola clade are discussed. 

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