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A cobalt-catalyzed intramolecular Markovnikov hydroalkoxycarbonylation and hydroaminocarbonylation of unactivated alkenes has been developed, enabling highly chemo- and regioselective synthesis of α-alkylated γ-lactones and α-alkylated γ-lactams in good yields. The mild reaction conditions allow use of mono-, di- and trisubstituted alkenes bearing a variety of functional groups. Preliminary mechanistic studies suggest the reaction proceeds through a CO-mediated hydrogen atom transfer (HAT) and radical-polar crossover (RPC) process, in which a cationic acylcobalt(IV) complex is proposed as the key intermediate.
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http://dx.doi.org/10.1002/anie.202412828 | DOI Listing |
Org Lett
August 2025
Division of Organic Synthesis, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
A cobalt(II)-catalyzed three-component synthesis of 2,5-substituted 1,3,4-oxadiazoles using -isocyaniminotriphenylphosphorane (NIITP), diazo compounds, and carboxylic acids has been developed. The tandem reaction involves a carbene transfer to NIITP, followed by the addition of the carboxylic acid to the -formed ketenimine and a subsequent intramolecular aza-Wittig reaction. The protocol tolerates a broad range of carboxylic acids and diazoacetates.
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May 2025
Department of Chemistry, University of Science and Technology of China, Hefei 230026, P. R. China.
An efficient and straightforward cobalt-catalyzed regioselective intramolecular hydrosilylation of olefins has been developed. Regioselectivity is controlled by the choice of ligands and substrates, which operate through two distinct mechanisms. This method has been successfully applied to both terminal and internal alkenes and phenyl and alkyl tethers between the silane and the alkene, demonstrating its versatility across a broad range of substrates.
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March 2025
Department of Chemistry, New York University, New York, New York 10003, United States.
Unsaturated hydroperoxides were synthesized from dienes using a regioselective cobalt-catalyzed hydroperoxidation reaction. Subsequent intramolecular oxa-Michael reactions in the presence of triethylammonium hydrochloride (HNEtCl) and catalytic EtN formed 1,2-dioxanes, in several cases with high diastereoselectivity. These 1,2-dioxanes could be transformed to their respective carboxylic acids, without affecting the integrity of the peroxide linkage, to form compounds with structures that resemble biologically active natural products.
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January 2025
Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zurich, Switzerland.
We report intramolecular photocatalyzed cycloisomerization of unactivated olefins with pendant nucleophiles. The reaction proceeds under mild conditions and utilizes guanidines, ureas, isoureas, isothioureas, and carbonates to yield several different five-, six-, and seven-membered heterocycles. Use of benzothiazinoquinoxaline as an organophotocatalyst and cobalt-salen catalyst obviates the need for a stoichiometric oxidant or reductant.
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December 2024
Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China.
A cobalt-catalyzed intramolecular [4 + 2] cycloaddition of cyclopropyl (CP)-capped dienes with ynes/enes/allene was reported, providing an efficient method toward a spiro[2.5]octene ring system found in natural products, such as illudin. The [4 + 2] cycloadducts can be converted into other compounds via CP chemistry.
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