Gold(i) catalysed regio- and stereoselective intermolecular hydroamination of internal alkynes was developed for the effective synthesis of a series of (Z)-functionalised vinylazoles under solvent free conditions. The catalytic hydrogenation of the resulting enamines leads to substituted saturated azoles in good yields.
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http://dx.doi.org/10.1039/c9ob00587k | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Freie Universitat Berlin, Chemistry and Biochemistry, Fabeckstraße 34-36, 14195, Berlin, GERMANY.
Neutral mesoionic carbenes (MICs) based on a 1,2,3-triazole core have had a strong impact on various branches of chemistry such as homogeneous catalysis, electrocatalysis, and photochemistry/photophysics. We present here the first general synthesis of anionic mesoionic carbenes (anMICs) based on a 1,2,3-triazole core and a borate backbone. The free anMIC is stable in solution under an inert atmosphere at low temperatures, and can be stored for several weeks.
View Article and Find Full Text PDFChemistry
January 2025
The GlaxoSmithKline Carbon Neutral Laboratories for Sustainable Chemistry, University of Nottingham, Jubilee Campus, Triumph Road, Nottingham, NG7 2TU, UK.
The nucleophilic propargylation of azinium ions with a propargylboronate proceeds efficiently under gold(I) catalysis. A range of N-alkylated pyridinium, quinolinium, and pyrazinium ions undergo propargylation with good yields and high regioselectivities to give various functionalized 1,4-dihydropyridines, 1,2-dihydropyridines, 1,4-dihydroquinolines, 1,2-dihydroquinolines, and 4,5-dihydropyrazines. No allenylation side-products are observed.
View Article and Find Full Text PDFTetrahedron Lett
October 2024
Department of Chemistry, University of California, Berkeley, CA 94720, USA.
Neutral dual hydrogen bond donors (HBDs) are effective catalysts that enhance the electrophilicity of substrates or the Lewis/Brønsted acidity of reagents through an anion-binding mechanism. Despite their success in various enantioselective organocatalytic reactions, their application to transition metal catalysis remains rare. Herein, we report the activation of gold(I) precatalysts by chiral ureas, leading to enantioselective hydroarylation of allenes with indoles.
View Article and Find Full Text PDFMolecules
November 2024
School of Chemistry, University College Dublin, Belfield, D04 V1W8 Dublin 4, Ireland.
Alkynylallenes offer the varied reactivity patterns of two different multiple bond linkages either separately or in concert. Initially, a short overview of their syntheses, structures, rearrangement mechanisms and synthetic utility, especially when treated with transition metal reagents such as gold(I), silver(I), platinum metals or metal carbonyls, is presented. Subsequently, we focus on the particular case of 1,2-dien-5-ynes (propargylallenes), whereby the shortness of the single atom bridge, and the consequent proximity of the allenyl and alkynyl moieties, facilitates metal-mediated interactions between them.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, the, Netherlands.
Incorporating noble metals in artificial metalloenzymes (ArMs) is challenging due to the lack of suitable soft coordinating ligands among natural amino acids. We present a new class of ArMs featuring a genetically encoded noble-metal-binding site based on a non-canonical thiophenol-based amino acid, 4-mercaptophenylalanine (pSHF), incorporated in the transcriptional regulator LmrR through stop codon suppression. We demonstrate that pSHF is an excellent ligand for noble metals in their low oxidation states.
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