Chemical reaction outcomes are often rationalized on the basis of independent analyses of steric and electronic effects. We applied three-dimensional free energy relationships correlating steric and electronic effects to design and optimize a ligand class for the enantioselective Nozaki-Hiyama-Kishi propargylation of ketones. The resultant mathematical model describing the steric and electronic parameter relationship is highly reliant on the synergistic interactions of these two effects.
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http://dx.doi.org/10.1126/science.1206997 | DOI Listing |
ACS Omega
January 2025
Unit of Excellence in Computational Molecular Science and Catalysis, and Division of Chemistry, School of Science, University of Phayao, Phayao 56000, Thailand.
The effectiveness of metallocene catalysts in the cationic ring-opening polymerization (cationic ROP) of ε-caprolactone (CL) is influenced by the choice of metallocene/borate systems, particularly their bulkiness. Recent research examines this effect on the initiation and propagation stages of cationic ROP. We conducted a density functional theory study on the precatalyst activation of cationic CL ROP by zirconocene/borate catalysts, where four models of zirconocene precatalysts (CpZrMe (), (MeCp)CpZrMe (), (MeCp)ZrMe (), and IndZrMe ()) were combined with boron cocatalysts B(CF) and [X][B(CF) ] (X = PhC or PhMeNH).
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States.
We report the photogeneration and characterization of an open-shell, terminal iron nitrido (L)Fe(N) using a sterically encumbered dipyrrin ligand environment. The Fe-N distance in the solid-state, zero-field Fe Mössbauer spectrum, and computational analysis are consistent with a triplet electronic ground state of the iron nitrido. Notably, the attenuation of Fe-N multiple bond character through occupying π* enables (i) primary C(sp)-H amination, (ii) H cleavage, (iii) aromatic C-C cleavage, and (iv) photocatalytic -atom transfer reactivity.
View Article and Find Full Text PDFFood Chem
January 2025
Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou, Henan 450001, China.
Flavors contain active aldehydes and ketones that react with glycerol and propylene glycol to form acetals and ketals. The identification of acetals and ketals is challenging due to the incomplete information in mass spectral libraries. This study examines the reaction kinetics of 36 aldehydes and ketones with propylene glycol and glycerol, and establishes a high sensitivity and throughput screening method for 185 acetals and ketals using GC-Orbitrap-MS.
View Article and Find Full Text PDFJ Chromatogr A
January 2025
Lab Essentials Applications Development, Sartorius Lab Instruments GmbH & Co. KG, Göttingen, Germany.
Adeno-associated viruses (AAV) are among the leading vectors for in vivo gene therapy. The purification of AAV remains a bottleneck as it typically requires multiple individual process steps, often resulting in product loss and high costs. Current downstream processes are usually serotype-specific and rely primarily on expensive affinity resins.
View Article and Find Full Text PDFCommun Chem
January 2025
National Institute of Chemistry, Hajdrihova 19, SI-1001, Ljubljana, Slovenia.
Iminophosphoranes with the general formula (RP═NR') have great potential in synthetic chemistry as valuable precursors/intermediates in organic synthesis or as building blocks for various organic compounds. However, the synthetic approaches and conditions to prepare iminophosphoranes are still poorly understood, limiting the utility of this chemistry for organic materials. In this article, a simple and efficient synthesis of previously unattainable poly(arylene iminophosphoranes) is reported.
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