New Pd-NHC complexes have been synthesized and employed for palladium-catalyzed direct arylation of pyrrole derivatives by using electron-deficient aryl chlorides as coupling partners. The desired coupling products were obtained in moderate to good yields by using 1 mol % of these air-stable palladium complexes. This is an advantage compared to the procedures employing air-sensitive phosphines, which have been previously shown to promote the coupling of aryl chlorides with heteroarenes.
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http://dx.doi.org/10.3762/bjoc.9.35 | DOI Listing |
J Am Chem Soc
December 2024
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States.
Nickel-catalyzed cross-electrophile coupling (XEC) reactions of (hetero)aryl electrophiles represent appealing alternatives to palladium-catalyzed methods for biaryl synthesis, but they often generate significant quantities of homocoupling and/or proto-dehalogenation side products. In this study, an informer library of heteroaryl chloride and aryl bromide coupling partners is used to identify Ni-catalyzed XEC conditions that access high selectivity for the cross-product when using equimolar quantities of the two substrates. Two different catalyst systems are identified that show complementary scope and broad functional-group tolerance, and time-course data suggest that the two methods follow different mechanisms.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
School of Petrochemical Engineering, Changzhou University, Changzhou 213164, P. R. China.
A photocatalytic sulfamoylation/5- cyclization of ()-'-arylidene--phenylmethacrylohydrazides with sulfamoyl chlorides was developed. The chemoselective intramolecular addition of the carbon-centered radical intermediate to the CN bond in the hydrazone motif gave the sulfamoylated pyrazolin-5-one. Besides, sulfonyl chlorides are also suitable reaction partners to access sulfonylated pyrazolin-5-ones.
View Article and Find Full Text PDFInorg Chem
December 2024
Departamento de Química Inorgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 19, 30100 Murcia, Spain.
Dicationic, -symmetrical, tris-chelate Pt(IV) complexes of general formula [Pt(trz)(N∧N)](OTf), bearing two cyclometalated 4-butyl-3-methyl-1-phenyl-1-1,2,3-triazol-5-ylidene (trz) ligands and one aromatic diimine [N∧N = 2,2'-bipyridine (bpy, ), 4,4'-di--butyl-2,2'-bipyridine (dbbpy, ), 4,4'-dimethoxi-2,2'-bipyridine (dMeO-bpy, ), 1,10-phenanthroline (phen, ), 4,7-diphenyl-1,10-phenanthroline (bphen, ), dipyrido[3,2-:2',3'-]phenazine (dppz, ), or 2,3-diphenylpyrazino[2,3-][1,10]phenanthroline (dpprzphen, )] are obtained through chloride abstraction from [PtCl(trz)] () using AgOTf in the presence of the corresponding diimine. Complexes show long-lived phosphorescence from LC excited states involving the diimine ligand, with quantum yields that reach 0.18 in solution and 0.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
Simple aryl chlorides represent challenging substrates in iron-catalyzed borylation. A combination of Li[B(Bu)pin-Bpin] as the borylating reagent and a catalyst formed in situ from iron(II) triflate and the commercially available N-heterocyclic carbene ligand, IMes, gives significantly improved activity and a much broader scope than previously reported iron-based catalysts. Iron triflate is also a good precatalyst for the borylation of aryl triflates─a previously unreported transformation─and in these cases the IMes ligand is not required.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Key Laboratory of New Materials and Facilities for Rural Renewable Energy of Ministry of Agriculture and Rural Affairs, College of Mechanical & Electrical Engineering, Henan International Joint Laboratory of Biomass Energy and Nanomaterials, Henan Agricultural University, Zhengzhou 450002, China. Electronic address:
This study developed a "one-pot" three-stage process using a "multifunctional" deep eutectic solvent (DES) containing choline chloride (ChCl), ethylene glycol (EG), and protonic acids for the production of phenolic monomers, furfural, and glucose. In the first stage, the DES effectively dissolved over 70 % of lignin and 78 % of hemicellulose while preserving aryl ether bonds in lignin due to the grafting of EG onto the aryl ether bonds. Concurrently, the retention of a near-quantitative amount of cellulose led to a glucose yield of >80 % after enzymatic saccharification.
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