The conformational preference of a cavity-based biaryl phosphine, namely 5-(2-diphenylphosphinyl-phenyl)-25,26,27,28-tetrapropyloxycalix[4]arene (L) has been investigated by density functional theory calculations. The analysis showed that the barrier to rotation about the C-C axle of the biaryl unit is only 10.7 kcal mol, this rendering possible access to conformers of two types, those in which the P lone pair sits at the cavity entrance and points to the calixarene interior, others with a more open structure where the P atom is located outside the cavity. As revealed by a single crystal X-ray diffraction study, the biaryl phosphine appears virtually as an atropisomer in the solid state in which the phosphorus atom lies totally out of the cavity defined by the four phenoxy rings.
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http://dx.doi.org/10.1039/d3dt00612c | DOI Listing |
Chemistry
January 2025
Osaka Metropolitan University: Osaka Koritsu Daigaku, Chemistry, 3-3-138 Sugimoto, Sumiyoshi-ku, 558-8585, Osaka, JAPAN.
Gold(I)-catalyzed intramolecular hydroarylation of dialkynyl(biaryl)phosphine oxides provided versatile benzo-fused phosphepine oxides. O-exo adducts were obtained as the major product, and O-endo adducts were the minor product. O-exo and O-endo indicate the position of an oxygen atom with respect to the central phosphepine framework.
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January 2025
Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, United Kingdom.
An aryl radical assay is used to provide information about the formation of aryl radicals from aryl halides in coupling reactions to arenes in the presence of palladium sources and under LED irradiation (λ = 456 nm). The assay uses 2-halo--xylenes as substrates. Aryl radical formation is indicated both by a defined product composition and by signature deuterium isotope effects.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China.
Although methods for synthesizing chiral phosphorus scaffolds are available, the potential of this molecular chirality remains largely unexplored. Herein, we present a remote desymmetrization of prochiral biaryl phosphine oxides through an organocatalytic asymmetric arylation. This metal-free approach enables the efficient synthesis of a wide range of densely functionalized P(V)-stereogenic compounds with good to excellent yields and satisfactory enantioselectivities.
View Article and Find Full Text PDFDalton Trans
January 2025
Department of Chemistry, Biology and Biotechnology, University of Perugia and CIRCC, Via Elce di Sotto 8, 06123, Perugia, Italy.
[(L1)Au(μ-H)MCp][BF] complexes (M = Mo and W) featuring cavity-shaped tris-2-(4,4'-di--butylbi-phenylyl)phosphine (L1) have been isolated. The tungsten derivative showed a remarkably fast reactivity in photolytic hydride transfer to generate the mononuclear gold hydride (L1)AuH. Both bimetallic adducts trap Ag cations, forming unprecedented {Au(μ-H)M(μ-H)Ag} trimetallic assemblies with destabilized Au-M interactions.
View Article and Find Full Text PDFJ Org Chem
December 2024
Université de Bourgogne, UFR des Sciences et Techniques, ICMUB UMR-CNRS 6302, BP 47870, 21078 Dijon Cedex, France.
Chiral diphosphines with a biphenyl bridge and the chirality borne by the phosphorus atoms and not due to the atropoisomery of the biaryl backbone have been scarcely studied. Herein, we report the asymmetric synthesis of the (,)-2,2'-bis(ferrocenylphenylphosphino)biphenyl (BipheP*) ligand and its application in Rh-catalyzed hydrogenation. The synthesis was based on the enantioselective preparation of P-chirogenic ferrocenyl(-bromophenyl)phenylphosphine by the reaction of -phosphine-borane with 1,2-dibromobenzene and its homocoupling into BipheP*.
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