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It takes al-kynes: The formation of furyl-substituted heterocycles from furanynes with donor groups on the furan-alkyne tether and mechanistic control experiments indicate the involvement of open-chained carbenium ions in the overall insertion of an alkyne into a C-C bond, rather than the usual spirocyclic intermediates.
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http://dx.doi.org/10.1002/chem.201200306 | DOI Listing |
J Am Chem Soc
September 2025
Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research, Ministry of Education of China, Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan 4100
While the conversion of simple cyclic ketones to lactams via carbon-carbon (C-C) bond cleavage can be accomplished through classical Beckmann and Schmidt rearrangements, these methods suffer from inherent limitations. Beyond regioselectivity challenges, they permit the incorporation of only a single nitrogen atom into the parent carbocyclic framework. Herein, an efficient approach to access medium-to-large sized lactams was developed through an alkyne migratory insertion enabled C-C bond activation of unstrained ketones.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, Texas 76798, United States.
Boravinylidenes are intermediates in 1,1-hydroboration reactions of alkynes en route to vinyl boranes. Unlike transition metal-vinylidene complexes, boravinylidenes have hitherto, not been crystallographically characterized. Pairing bis(trimethylsilyl)ethyne with an extremely potent hydroboration reagent, bis(1-methyl--carboranyl)borane, enables crystallization and characterization of a boravinylidene.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr, 45470, Germany.
The readily accessible iron complex [Cp*FeCl(tmeda)] is an effective catalyst for the highly regio- and stereoselective trans-hydrostannylation of terminal alkyl alkynes, affording a type of alkenylstannanes that is difficult to make otherwise. The RSn- moiety is faithfully delivered to the terminal C-atom, unless a propargylic or homo-propargylic ─OH or ─NH group is present in the substrate, which (partly or fully) inverts the regiochemical course; this steering effect, however, can be switched off upon protection of the protic site. The trans-addition likely starts by insertion of the [Cp*FeCl] fragment into the RSn─H bond, followed by a migratory insertion of the ligated alkyne into the Fe─Sn unit of the Fe(IV) species thus formed.
View Article and Find Full Text PDFInorg Chem
August 2025
Department of Chemistry, University of York, Heslington, YorkYO10 5DD, U.K.
An investigation into the effect of a phosphine coligand on the activation of precatalysts for manganese-catalyzed C-H bond functionalization is reported. Although simple precatalysts [MnBr(CO)] and [Mn(CO)] are used extensively in these reactions, there is a dearth of alternate precatalyst structures, which has hindered the development of structure-activity relationships. In this work, the effect of substituting a carbonyl ligand for a phosphine ligand is reported.
View Article and Find Full Text PDFOrg Lett
August 2025
College of Chemistry and Chemical Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
An alkyl sulfinate anion-mediated hydrosulfonylation of alkenes/alkynes with alkyl bromides involving SO insertion has been developed for the synthesis of alkyl sulfones. Sodium dithionite (NaSO) acts as both an SO surrogate and a single-electron donor, thereby obviating the need for metal catalysts or metallic reductants. This protocol features broad substrate scope and high functional group tolerance, accommodating a range of bioactive scaffold molecules such as citronellol, estrone, borneol, and cholesterol.
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