Ethynyldimesitylborane (1) is synthesised via salt elimination and its reactivity towards NHCs is studied. Depending on their size, NHCs attack either at the boron atom or at the β-alkynyl carbon atom. Steric control over the reaction was probed by reactions with N-heterocyclic carbenes yielding a carbene-borane adduct (2), a 1-boraindane (3), and the first structurally characterised borataallene (4).
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Beilstein J Org Chem
January 2025
Department of Organic Chemistry, Faculty of Natural Science, Comenius University Bratislava, Mlynská dolina, Ilkovičova 6, 842 15 Bratislava, Slovakia.
Axial chirality is present in a variety of naturally occurring compounds, and is becoming increasingly relevant also in medicine. Many axially chiral compounds are important as catalysts in asymmetric catalysis or have chiroptical properties. This review overviews recent progress in the synthesis of axially chiral compounds via asymmetric organocatalysis.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan.
The chemical reactivity between benzene and the "naked" acyclic carbene-like (G13X) species, having two bulky N-heterocyclic boryloxy ligands at the Group 13 center, was theoretically assessed using density functional theory computations. Our theoretical studies show that (BX) preferentially undergoes C-H bond insertion with benzene, both kinetically and thermodynamically, whereas the (AlX) analogue favors a reversible [4 + 1] cycloaddition. Conversely, the heavier carbene analogues ((GaX), (InX), and (TlX)) are not expected to engage in a reaction with benzene.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Universitat Bern, Department of Chemistry and Biochemistry, Freiestrasse 3, 3012, Bern, SWITZERLAND.
Isotope Exchange processes are becoming the preferred way to prepare isotopically labelled molecules, avoiding the redesign of multistep synthetic protocols. In the case of deuterium incorporation, the most used strategy has employed transition metals, that offer high reactivity under mild reaction conditions. Despite their success, the trade-off is that these metals are precious, and often exhibit high toxicity.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, BC V8W 3 V6, Canada.
A charge-tagged N-heterocyclic carbene (NHC) has been synthesized and its utility in allowing the dynamic behaviour of metal complexes to be monitored in real time using electrospray ionization mass spectrometry demonstrated. This compound was used to prepare different metal-NHC complexes, and the kinetic behaviour of complex formation and ligand exchange was monitored in real time through the use of pressurized sample infusion electrospray mass spectrometry (PSI-ESI-MS).
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Faculty of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan.
The factors controlling the catalytic activity in photochemical hydrogen evolution reaction (HER) are studied in detail for two macrocyclic cobalt compounds bearing two N-heterocyclic carbenes and two pyridyl donors ( and , where has a methoxy substituent on each pyridyl ligand). The present study adopts an aqueous photosystem consisting of EDTA, [Ru(bpy)] (bpy = 2,2'-bipyridine), and MV (MV = methylviologen) at pH = 5. Both catalysts are shown to promote HER in a similar efficiency (TON = 12-13 in 6 h), revealing a minor contribution of the electron-donating methoxy substituents.
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