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[reaction: see text] The coupling of enyne-imines with Fischer carbene complexes leads to the formation of alkenylpyrrole derivatives. Maximum yields of pyrrole adducts were obtained using N,N-dimethylhydrazones. A mechanism involving alkyne insertion followed by nucleophilic attack of the imine nitrogen at the intermediate alkenylcarbene complex was proposed.
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http://dx.doi.org/10.1021/ol034414j | DOI Listing |
Chemistry
July 2025
Institute of Inorganic Chemistry, Graz University of Technology, Stremayrgasse 9/IV, Graz, 8010, Austria.
In this contribution, a metal-free synthetic approach toward isolable bisacylgermylenes, a novel class of germylenes, is described. Starting from tetra(2,4,6-trimethylbenzoyl)germane 1 and bromo-tris(2,4,6-trimethylbenzoyl)germane 3, we demonstrate that simple treatment with NHCs leads to two distinct types of reactivity: acyl abstraction and germylene stabilization. Reaction of 1 with NHCs produces imidazolium-substituted germenolates 2a,b via a hydrogen atom transfer (HAT) mechanism.
View Article and Find Full Text PDFNat Commun
May 2025
State Key Laboratory of Anti-Infective Drug Discovery and Development, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China.
Metal-catalyzed hydrosilylation of alkynes is recognized as a straightforward and atom economic method for synthesizing alkenylsilanes. While substantial advancements have been made with terminal alkynes, achieving precise regio- and stereocontrol with unsymmetrical internal alkynes remains a significant challenge. In this study, we report the utilization of an intriguing β-boron effect in metal catalysis, enabling an exclusively regioselective Ru-catalyzed hydrosilylation of propargylic N-methyliminodiacetic acid boronates (B(MIDA)) to synthesize alkenylsilanes.
View Article and Find Full Text PDFChem Sci
May 2025
Department of Organic and Macromolecular Chemistry, Ghent University Krijgslaan 281-S4 9000 Ghent Belgium
This study explores a novel N-heterocyclic carbene-mediated siloxane exchange mechanism, laying the foundation for designing covalent adaptable networks (CANs) with high temperature stability (>200 °C) for dynamic covalent chemistry. Small molecule siloxane compounds, obtained by hydrosilylation reactions, are used to demonstrate siloxane-exchange a mechanism supported by density functional theory. The proposed mechanism presents an equilibrium, at elevated temperatures, between an imidazolium salt and its free carbene form, which is the catalytically active species.
View Article and Find Full Text PDFNat Commun
March 2025
Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, D-37077, Göttingen, Germany.
The ubiquity of N-heterocyclic carbenes (NHCs) in diverse areas of chemical research typically arises from their potent stabilising capabilities and role as innocent spectators to stabilise otherwise non-bottleable compounds and complexes. This has, until now, been particularly true for NHC-stabilised stannylenes, with no exceptions reported thus far. Herein, we demonstrate that the combination of heteroleptic terphenyl-/amido-based stannylenes and tetra-alkyl substituted NHCs renders the corresponding NHC-ligated stannylenes highly reactive, yet isolable.
View Article and Find Full Text PDFDalton Trans
May 2025
Institut für Anorganische Chemie, Georg-August-Universität Göttingen, Tammannstraße 4, D-37077 Göttingen, Germany.
We present the synthesis and characterization of the parent isolable monomeric triplet titanocene complex, stabilized by the N-heterocyclic carbene (NHC) IMe. Investigated by SQUID magnetometry and quantum-chemical calculations, reactivity studies of the titanium precursor [CpTi(btmsa)] (2) with the NHC IPrMe and the zirconocene complex [CpZr(py)(btmsa)] (1) revealed divergent reactivity patterns, highlighting the role of steric and electronic effects in stabilization.
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