Methyl substitution at the double bond of -alkenyl anilides influences both the preferred conformation and the susceptibility to acidic hydrolysis. The R-substituted amide favors the trans conformation, whereas amides substituted at R or R favor the cis conformation. Substitution at the R and R positions increases the ratio of the trans conformer. DFT study indicated that these conformational preferences can be explained in terms of substituent-induced torsion twisting of the -alkenyl moiety relative to the amide plane. R substitution enhances the susceptibility to acidic hydrolysis, whereas R or R substitution increases the stability. The effect of the double bond on the conformational effect was showcased by contrasting the preferred conformation of R-substituted anilide (trans) and hydrogenated -isopropyl amide (cis).
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http://dx.doi.org/10.1021/acs.joc.3c01487 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Haihe Laboratory of Sustainable Chemical Transformations, Nankai University 94 Weijin Road, Tianjin, China.
The diverse utility of acyclic vinylsilanes has driven the interest in the synthesis of enantioenriched vinylsilanes bearing a Si-stereogenic center. However, the predominant approaches for catalytic asymmetric generation of Si-stereogenic vinylsilanes have mainly relied on transition metal-catalyzed reactions of alkynes with different silicon sources. Here we successfully realize the enantioselective synthesis of linear silicon-stereogenic vinylsilanes with good yields and enantiomeric ratios from simple alkenes under rhodium catalysis.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Jilin Key Laboratory of Solid-State Laser Technology and Application, School of Physics, Changchun University of Science and Technology, Changchun 130022 China. Electronic address:
HBT-DPI was a single-molecule multi-conformational fluorescent material and had unique applications for hydrophobic/hydrophilic mapping on large-scale heterogeneous surfaces. In this paper, the different proton transfer processes and luminescence mechanisms of HBT-DPI in Dichloromethane (DCM, no hydrogen bond (HB) receptor) and N, N-Dimethylformamide (DMF, HB receptor) solvents were systematically studied. Using the quantum chemistry method, the stable structures of HBT-DPI in two solvents were determined based on the Boltzmann distribution.
View Article and Find Full Text PDFJ Colloid Interface Sci
January 2025
School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001 China. Electronic address:
Nickel-rich cobalt-free layered oxide cathode with Ni contents no fewer than 90 % has received extensive attention in the field of lithium-ion batteries due to its excellent specific capacity and low cost, but serious capacity degeneration induced by structural deterioration and interfacial instability greatly hamper their further development. Herein, the Sb-modified LiNiMnO materials from the interface to interior have been designed and fabricated to overcome the above issues. On the one hand, the introduction of Sb-ion in interior of grains can generate Sb-O chemical bond with high dissociation energy, which contributes to reinforce the chemical and structural stability.
View Article and Find Full Text PDFThe hexadehydro-Diels-Alder (HDDA) reaction is a cycloisomerization between a conjugated diyne and a tethered diynophile that generates -benzyne derivatives. Considerable fundamental understanding of aryne reactivity has resulted from this body of research. The multi-yne cycloisomerization substrate is typically pre-formed and the (rate-limiting) closure of this diyne/diynophile pair to produce the isomeric benzyne generally requires thermal input, often requiring reaction temperatures of >100 °C and times of 16-48 h to achieve near-full conversion.
View Article and Find Full Text PDFCarbohydr Res
January 2025
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, 81531-990, Curitiba, PR, Brazil. Electronic address:
Sea cucumbers are widely used in oriental cuisine due to their medicinal properties. Antioxidant, antifungal, antiviral, anticancer and neuroprotective activities have already been identified in several species and in different tissues. Among the class of compounds with biological activity are cerebrosides, which have important functions for the proper functioning of cells, especially neuronal cells.
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