The first enantio- and diastereoselective approach to alpha-alkoxy-substituted syn-beta-hydroxyesters through highly efficient catalytic asymmetric transfer hydrogenation via dynamic kinetic resolution reactions from the corresponding racemic beta-ketoesters is described. In this atom-economical process, two contiguous stereogenic centers are generated simultaneously with an excellent diastereoselectivity (up to 99/1) and enantioselectivity (up to 99%), allowing a rapid access to a wide variety of aromatic and heteroaromatic monodifferentiated syn-1,2-diols.
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http://dx.doi.org/10.1021/ol101451s | DOI Listing |
ACS Nano
December 2024
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Ultrafast thermal switches are pivotal for managing heat generated in advanced solid-state applications, including high-speed chiplets, thermo-optical modulators, and on-chip lasers. However, conventional phonon-based switches cannot meet the demand for picosecond-level response times, and existing near-field radiative thermal switches face challenges in efficiently modulating heat transfer across vacuum gaps. To overcome these limitations, we propose an ultrafast thermal switch design based on pump-driven transient polaritons in asymmetric terminals.
View Article and Find Full Text PDFNMR Biomed
February 2025
Department of Radiology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, China.
Asymmetry is a natural characteristic of Parkinson's disease (PD), which can be used to distinguish PD from atypical parkinsonism. Chemical exchange saturation transfer (CEST) has demonstrated value in reflecting the subtle changes related to neuron loss and abnormal protein accumulation in PD but has not been used to investigate asymmetry in PD. This study aimed to examine asymmetrical changes in the mesencephalic nucleus of PD patients with motor asymmetry using four-pool CEST analysis and to explore the relationship between imaging asymmetry and motor asymmetry.
View Article and Find Full Text PDFJ Colloid Interface Sci
December 2024
College of Chemistry and Materials Engineering, Bohai University, Jinzhou 121013, China. Electronic address:
The unique structure and strong interaction of multiphase hybrid materials have garnered significant attention as prospective candidates for electrode materials in the realm of energy storage. The present study presents a rational design of a functional NiSe-CoSe/N, B double-doped carbon hybrid composite (NCS/C), resulting in the emergence of various novel cooperative regulatory mechanisms involving: (i) the heterogeneous structure of NiSe and CoSe generates built-in electric fields to increase electron mobility; (ii) the incorporation of polyatomic double-doped carbon (N, and B) expedites electron transfer rate; intriguingly, (iii) ionic liquids not only serve as polyatomic dopants in the reaction system but also influence the microstructure of the composite. Benefiting from these synergistic effects, the NCS/C hybrid exhibits remarkable charge storage capacity and rapid electrochemical kinetics, driven by its multi-fold hollow structure and multicomponent cooperative modulation.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Qingdao University of Science and Technology, college of materials science and engineering, Zhengzhou Road 53#, 266042, Qingdao, CHINA.
The catalytic efficiency of natural enzymes depends on the precise electronic interactions between active centers and cofactors within a three-dimensional (3D) structure. Single-atom nanozymes (SAzymes) attempt to mimic this structure by modifying metal active sites with molecular ligands. However, SAzymes struggle to match the catalytic efficiency of natural enzymes due to constraints in active site proximity, quantity, and the inability to simulate electron transfer processes driven by internal electronic structures of natural enzymes.
View Article and Find Full Text PDFDalton Trans
December 2024
Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan.
This study investigates the mechanism of prototropic tautomerization in metal-bound asymmetric pyrazole (R-PzH) ligands during Cu(II)-mediated PzH-MeCN coupling reactions. Intrinsic prototropic tautomerization of metal-bound ligands has not been previously documented. Various new bis-pyrazolylamidino Cu(II) complexes, [Cu(R-Pz(HNC(Me)))(ClO)], from the coupling reaction, and tetrakis pyrazole Cu(II) complexes, [Cu(R-PzH)(ClO)], with symmetric and asymmetric -monosubstituted R-PzH ligands were synthesized and characterized.
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