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991.
Jie Yang Xiao‐Ming Zhang Fu‐Min Zhang Shao‐Hua Wang Yong‐Qiang Tu Zhen Li Xi‐Chao Wang Hong Wang 《Angewandte Chemie (International ed. in English)》2020,59(22):8471-8475
An enantioselective aldehyde α‐alkylation/semipinacol rearrangement was achieved through organo‐SOMO catalysis. The catalytically generated enamine radical cation serves as a carbon radical electrophile that can stereoselectively add to the alkene of an allylic alcohol and initiate ensuing ring‐expansion of cyclopropanol or cyclobutanol. This tandem reaction enables the production of a wide range of nonracemic functionalizable α‐quaternary‐δ‐carbonyl cycloketones in high yields and excellent enantioselectivity from simple aldehydes and allylic alcohols. As a key step, the intramolecular reaction was also successfully applied in the asymmetric total synthesis of (+)‐cerapicol. 相似文献
992.
Jing Zhao Yanan Zhu Xuehong Song Yuanyuan Xiao Guowei Su Xinyue Liu Zhangjie Wang Yongmei Xu Jian Liu David Eliezer Trudy F. Ramlall Guy Lippens James Gibson Fuming Zhang Robert J. Linhardt Lianchun Wang Chunyu Wang 《Angewandte Chemie (International ed. in English)》2020,59(5):1818-1827
Prion‐like transcellular spreading of tau in Alzheimer's Disease (AD) is mediated by tau binding to cell surface heparan sulfate (HS). However, the structural determinants for tau–HS interaction are not well understood. Microarray and SPR assays of structurally defined HS oligosaccharides show that a rare 3‐O‐sulfation (3‐O‐S) of HS significantly enhances tau binding. In Hs3st1?/? (HS 3‐O‐sulfotransferase‐1 knockout) cells, reduced 3‐O‐S levels of HS diminished both cell surface binding and internalization of tau. In a cell culture, the addition of a 3‐O‐S HS 12‐mer reduced both tau cell surface binding and cellular uptake. NMR titrations mapped 3‐O‐S binding sites to the microtubule binding repeat 2 (R2) and proline‐rich region 2 (PRR2) of tau. Tau is only the seventh protein currently known to recognize HS 3‐O‐sulfation. Our work demonstrates that this rare 3‐O‐sulfation enhances tau–HS binding and likely the transcellular spread of tau, providing a novel target for disease‐modifying treatment of AD and other tauopathies. 相似文献
993.
Pengpeng Shao Ruxin Yao Ge Li Mengxi Zhang Shuai Yuan Xiaoqi Wang Yuhao Zhu Xianming Zhang Lin Zhang Xiao Feng Bo Wang 《Angewandte Chemie (International ed. in English)》2020,59(11):4401-4405
Commercial ultrafiltration membranes have proliferated globally for water treatment. However, their pore sizes are too large to sieve gases. Conjugated microporous polymers (CMPs) feature well‐developed microporosity yet are difficult to be fabricated into membranes. Herein, we report a strategy to prepare molecular‐sieving membranes by partitioning the mesoscopic channels in water ultrafiltration membrane (PSU) into ultra‐micropores by space‐confined polymerization of multi‐functionalized rigid building units. Nine CMP@PSU membranes were obtained, and their separation performance for H2/CO2, H2/N2, and H2/CH4 pairs surpass the Robeson upper bound and rival against the best of those reported membranes. Furthermore, highly crosslinked skeletons inside the channels result in the structural robustness and transfer into the excellent aging resistance of the CMP@PSU. This strategy may shed light on the design and fabrication of high‐performance polymeric gas separation membranes. 相似文献
994.
Peng‐Ju Xia Dan Song Zhi‐Peng Ye Yuan‐Zhuo Hu Jun‐An Xiao Hao‐Yue Xiang Xiao‐Qing Chen Hua Yang 《Angewandte Chemie (International ed. in English)》2020,59(17):6706-6710
A photoinduced SET process enables the direct B?H bond activation of NHC–boranes. In contrast to common hydrogen atom transfer (HAT) strategies, this photoinduced reaction simply takes advantage of the beneficial redox potentials of NHC–boranes, thus obviating the need for extra radical initiators. The resulting NHC–boryl radical was used for the borylation of a wide range of α‐trifluoromethylalkenes and alkenes with diverse electronic and structural features, providing facile access to highly functionalized borylated molecules. Labeling and photoquenching experiments provide insight into the mechanism of this photoinduced SET pathway. 相似文献
995.
Lin Yan Ling-Hui Wang Xie Li Ao Li Qi-Min Xiao 《Phosphorus, sulfur, and silicon and the related elements》2020,195(9):740-746
AbstractTreatment of the starting complex [Fe2(CO)6{μ-SCH2CH(CH2OH)S}] (1) with 2-(diphenylphosphino)benzoic acid in the presence of N,N’-dicyclohexylcarbodiimide and 4-dimethylaminopyridine gave the corresponding ester derivative [Fe2(CO)6{μ-SCH2CH(CH2O2CC6H4PPh2-2)S}] (2) in 92% yield. Further treatment of complex 2 with one equivalent of Me3NO · 2?H2O as the decarbonylating agent yielded diphenylphosphino-substituted complex [Fe2(CO)5{μ-SCH2CH(CH2O2CC6H4PPh2-2)S}] (3) in 79% yield. Both complexes were characterized by elemental analysis, spectroscopy, as well as by X-ray crystallography. Additionally, the electrochemical properties of these complexes were studied by cyclic voltammetry. 相似文献
996.
997.
Zhi‐Chao Jiang Yao‐Yu Xiao Lu Yin Li Han Yue Zhao 《Angewandte Chemie (International ed. in English)》2020,59(12):4925-4931
Novel main‐chain liquid crystalline Diels—Alder dynamic networks (LCDANs) were prepared that exhibit unprecedented ease for actuator programming and reprocessing compared to existing liquid crystalline network (LCN) systems. Following cooling from 125 °C, LCDANs are deformed with aligned mesogens self‐locked at room temperature by slowly formed Diels–Alder (DA) bonds, which allows for the formation of solid 3D actuators capable of reversible shape change, and strip walker and wheel‐capable light‐driven locomotion upon either thermally or optically induced order–disorder phase transition. Any actuator can readily be erased at 125 °C and reprogrammed into a new one under ambient conditions. Moreover, LCDANs can be processed directly from melt (for example, fiber drawing) and from solution (for example, casting tubular actuators), which cannot be achieved with LCNs using exchangeable covalent bonds. The combined attributes of LCDANs offer significant progress toward developing easily programmable/processable LCN actuators. 相似文献
998.
Min Zhou Yuxin Qian Jiayang Xie Wenjing Zhang Weinan Jiang Ximian Xiao Sheng Chen Chengzhi Dai Zihao Cong Zhemin Ji Ning Shao Longqiang Liu Yuequn Wu Runhui Liu 《Angewandte Chemie (International ed. in English)》2020,59(16):6412-6419
Peptides have important biological functions. However, their susceptibility to proteolysis limits their applications. We demonstrated here for the first time, that poly(2‐oxazoline) (POX) can work as a functional mimic of peptides. POX‐based glycine pseudopeptides, a host defense peptide mimic, had potent activities against methicillin‐resistant S. aureus, which causes formidable infections. The POX mimic showed potent activity against persisters that are highly resistant to antibiotics. S. aureus did not develop resistance to POX owning to the reactive oxygen species related antimicrobial mechanism. POX‐treated S. aureus is sensitive to common antibiotics, demonstrating no observable antimicrobial pressure or cross‐resistance in using antimicrobial POX. This study highlights POX as a new type of functional mimic of peptides and opens new avenues in designing and exploring peptide mimetics for biological functions and applications. 相似文献
999.
A Diffusion‐‐Reaction Competition Mechanism to Tailor Lithium Deposition for Lithium‐Metal Batteries
Xiao‐Ru Chen Yu‐Xing Yao Chong Yan Rui Zhang Xin‐Bing Cheng Qiang Zhang 《Angewandte Chemie (International ed. in English)》2020,59(20):7743-7747
Lithium metal is recognized as one of the most promising anode materials owing to its ultrahigh theoretical specific capacity and low electrochemical potential. Nonetheless, dendritic Li growth has dramatically hindered the practical applications of Li metal anodes. Realizing spherical Li deposition is an effective approach to avoid Li dendrite growth, but the mechanism of spherical deposition is unknown. Herein, a diffusion‐reaction competition mechanism is proposed to reveal the rationale of different Li deposition morphologies. By controlling the rate‐determining step (diffusion or reaction) of Li deposition, various Li deposition scenarios are realized, in which the diffusion‐controlled process tends to lead to dendritic Li deposition while the reaction‐controlled process leads to spherical Li deposition. This study sheds fresh light on the dendrite‐free Li metal anode and guides to achieve safe batteries to benefit future wireless and fossil‐fuel‐free world. 相似文献
1000.
Lei Jiang Haizhen Ding Siyu Lu Ting Geng Guanjun Xiao Bo Zou Hong Bi 《Angewandte Chemie (International ed. in English)》2020,59(25):9986-9991
Photoactivation in CdSe/ZnS quantum dots (QDs) on UV/Vis light exposure improves photoluminescence (PL) and photostability. However, it was not observed in fluorescent carbon quantum dots (CDs). Now, photoactivated fluorescence enhancement in fluorine and nitrogen co‐doped carbon dots (F,N‐doped CDs) is presented. At 1.0 atm, the fluorescence intensity of F,N‐doped CDs increases with UV light irradiation (5 s–30 min), accompanied with a blue‐shift of the fluorescence emission from 586 nm to 550 nm. F,N‐doped CDs exhibit photoactivated fluorescence enhancement when exposed to UV under high pressure (0.1 GPa). F,N‐doped CDs show reversible piezochromic behavior while applying increasing pressure (1.0 atm to 9.98 GPa), showing a pressure‐triggered aggregation‐induced emission in the range 1.0 atm–0.65 GPa. The photoactivated CDs with piezochromic fluorescence enhancement broadens the versatility of CDs from ambient to high‐pressure conditions and enhances their anti‐photobleaching. 相似文献