An N-heterocyclic carbene-phosphine iridium complex system was found to be a very efficient catalyst for the methylation of ketone via a hydrogen transfer reaction. Mild conditions together with low catalyst loading (1 mol %) were used for a tandem process which involves the dehydrogenation of methanol, C=C bond formation with a ketone, and hydrogenation of the new generated double bond by iridium hydride to give the alkylated product. Using this iridium catalyst system, a number of branched ketones were synthesized with good to excellent conversions and yields.
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http://dx.doi.org/10.1002/chem.201405990 | DOI Listing |
Org Biomol Chem
July 2024
Key Laboratory of Green Chemistry & Technology, Ministry of Education College of Chemistry, Sichuan University Chengdu 610064, P. R. China.
Herein, the synthesis of branched α,β-unsaturated amides by a hydroaminocarbonylation reaction of alkynes with various amine substrates such as aromatic amines, aliphatic amines, solid amine sources like NHHCO, and even strongly basic piperidines is reported, using a Pd(OAc)/hybrid N-heterocyclic carbene-phosphine-phosphine (CPP) catalytic system. The reactions feature no additives, wide substrate scope, high selectivity (b/l > 99 : 1) and excellent yields. Mechanistic studies have disclosed that the reaction takes place a palladium hydride pathway.
View Article and Find Full Text PDFChem Asian J
June 2023
Organometallics and Materials Chemistry Lab, Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, Telangana, 502285, India.
Phosphine coordinated copper(I)-N-heterocyclic carbene complexes have emerged as an efficient material in catalysis and light-emitting applications. In this study, a gentle and sustainable approach to the copper(I)-carbene phosphine complexes is reported through an efficient C=Se activation protocol. The complexes [(Py^NHC)Cu(PPh ) ]X, X=BF (1), ClO (2), PF (3) and OTf (4); Py^NHC=3-isopropyl-1-(pyridin-2-yl)-imidazol-2-ylidene, and [(Py^NHC)Cu(PPh )(X)], X=Br (5) and I (6) have been synthesized by treating 1-isopropyl-3-(pyridin-2-yl)-imidazole-2-selone with corresponding copper(I) precursors and triphenylphosphine.
View Article and Find Full Text PDFChem Rev
July 2021
Inorganic Chemistry Laboratory, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, 15771 Athens, Greece.
The chemistry of discrete molecular chains constituted by metals in low oxidation states, displaying metal-metal proximity and stabilized by suitable metal-bridging, assembling ligands comprising at least one soft donor atom is comprehensively reviewed; complexes with a single (hard or soft) bridging atom (., μ-halide, μ-sulfide, or μ-PR .) as well as "closed" metal arrays (that fall in the realm of cluster chemistry) are excluded.
View Article and Find Full Text PDFOrg Biomol Chem
April 2021
School of Materials Science & Engineering, PCFM Lab, School of Chemistry, Sun Yat-sen University, Guangzhou 510275, P. R. China.
Metal hydride complexes are key intermediates for N-alkylation of amines with alcohols by the borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols and the hydrogenation of imines. Herein we report ruthenium(ii) complexes with hetero-bidentate N-heterocyclic carbene (NHC)-phosphine ligands, which realize smart pathway selection in the N-alkylated reaction via reactivity tuning of [Ru-H] species by hetero-bidentate ligands.
View Article and Find Full Text PDFBeilstein J Org Chem
August 2020
Dpt. of Inorganic and Organic Chemistry, Supramolecular and Sustainable Chemistry Group, University Jaume I, Avda Sos Baynat s/n, E-12071-Castellon, Spain.
The combination of supported ionic liquids and immobilized NHC-Pd-RuPhos led to active and more stable systems for the Negishi reaction under continuous flow conditions than those solely based on NHC-Pd-RuPhos. The fine tuning of the NHC-Pd catalyst and the SILLPs is a key factor for the optimization of the release and catch mechanism leading to a catalytic system easily recoverable and reusable for a large number of catalytic cycles enhancing the long-term catalytic performance.
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