Asymmetric catalysis with readily available, cheap, and non-toxic alkaline earth metal catalysts represents a sustainable alternative to conventional synthesis methodologies. In this context, we describe the development of a first Mg -catalyzed enantioselective hydroboration providing the products with excellent yields and enantioselectivities. NMR spectroscopy studies and DFT calculations provide insights into the reaction mechanism and the origin of the enantioselectivity which can be explained by a metal-ligand cooperative catalysis pathway involving a non-innocent ligand.
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http://dx.doi.org/10.1002/anie.201908012 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Western University, Chemistry, 1151 Richmond Street, N6A3K7, London, CANADA.
This work addresses fundamental questions that deepen our understanding of secondary coordination sphere effects on carbon dioxide (CO2) reduction using derivatized hydride analogues of the type, [Cp*Fe(diphosphine)H] (Cp* = C5Me5-) - a well-studied family of organometallic complex - as models. More precisely, we describe the general reactivity of [(Cp*-BR2)Fe(diphosphine)H], which contains an intramolecularly positioned Lewis acid, and its cooperative reactivity with CO2. Control experiments underscore the critical nature of borane incorporation for CO2 to reduced products, a reaction that does not occur for unfunctionalized [Cp*Fe(diphosphine)H]).
View Article and Find Full Text PDFMolecules
December 2024
Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aramaki, Aoba-ku, Sendai 980-8578, Japan.
Dihydrogen activation by metallogermylenes was investigated experimentally and theoretically. A neutral NHC-coordinated chlorometallogermylene was synthesized and converted to a cationic base-free metallogermylene of molybdenum via chloride abstraction. The cationic molybdogermylene showed enhanced reactivity toward H compared to the tungsten analog.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Martin-Luther-Universitat Halle-Wittenberg, Department of Chemistry, Kurt-Mothes-Str. 2, 06120, Halle, GERMANY.
A pronounced nucleophilicity in combination with a distinct redox non-innocence is a unique feature of a coordinated ligand, which in the current case, leads to unprecedented carbon-centered reactivity patterns: A carbodiphosphorane-based (CDP) pincer-type rhodium complex allows to cleave two C-Cl-bonds of geminal dichlorides via two consecutive SN2-type oxidative additions resulting in the formation of a stabilized carbene fragment. In the presence of a suitable reductant the carbene fragment can even be converted into olefines or hydrodehalogenation products in a catalytic reaction. The developed method can also be used to convert chlorofluorocarbons (CFCs) such as CH2ClF to fluoromethane and methane.
View Article and Find Full Text PDFDalton Trans
December 2024
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
Effective activation of small molecules (alcohol, phenol, ketones, amine, .) by a hydrogen-bridged bis(silylene) complex, which has two adjacent Lewis acidic centers and a hydridic bridging hydrogen with weak Si⋯H bonds, is described, along with product characterization by NMR and X-ray diffraction studies.
View Article and Find Full Text PDFJ Org Chem
December 2024
Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, Rajasthan 342037, India.
An Earth-abundant Mn-PNP pincer complex-catalyzed terpenylation of cyclic and acyclic ketones and secondary alcohol 1-phenylethanol using isoprenoid derivatives prenol, nerol, phytol, solanesol, and E-farnesol as allyl surrogates is reported. The C-C coupling reactions are green and atom-economic, proceeding via dehydrogenation of alcohols following a hydrogen autotransfer methodology aided by metal-ligand cooperation.
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