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排序方式: 共有311条查询结果,搜索用时 15 毫秒
1.
Elaine Tsui Anthony J. Metrano Yuto Tsuchiya Prof. Robert R. Knowles 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(29):11943-11947
We report a catalytic, light-driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible-light irradiation in the presence of an IrIII-based photoredox catalyst, a Brønsted base catalyst, and a hydrogen-atom transfer (HAT) co-catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O−H bonds through a proton-coupled electron-transfer mechanism. This method exhibits a broad substrate scope and high functional-group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented. 相似文献
2.
3.
Vickie Tsui Daniel F. Ortwine Jeffrey M. Blaney 《Journal of computer-aided molecular design》2017,31(3):287-291
Computational chemistry/informatics scientists and software engineers in Genentech Small Molecule Drug Discovery collaborate with experimental scientists in a therapeutic project-centric environment. Our mission is to enable and improve pre-clinical drug discovery design and decisions. Our goal is to deliver timely data, analysis, and modeling to our therapeutic project teams using best-in-class software tools. We describe our strategy, the organization of our group, and our approaches to reach this goal. We conclude with a summary of the interdisciplinary skills required for computational scientists and recommendations for their training. 相似文献
4.
R. R. Silva L. A. Vieira Mendes K. H. Tsui R. A. De Simone Zanon A. L. de Oliveira C. E. Fellows 《Applied physics. B, Lasers and optics》2011,104(3):679-687
Nitrogen laser performance with TE configuration and wedge electrodes is analyzed with background ionization in the laser
discharge channel by α particles at a low exposition rate. With the bias ionization, the laser power presents two peaks as a function of gas pressure,
with one at the normal low pressure, without bias ionization, and the other at high pressure generated by bias ionization.
A simple theoretical model has been developed in a trial to understand this behavior. This model was first tested in later
results for a TE configuration nitrogen laser, with flat electrodes, without and with bias ionization. It has been observed
that due to the competition between electrode shielding by positively charged α particles and bulk ionization by impact, the laser energy is suppressed with pressure below 50 Torr and enhanced above it. 相似文献
5.
Qiao Ma Yanhui Wang Gavin Chit Tsui 《Angewandte Chemie (International ed. in English)》2020,59(28):11293-11297
A stereoselective Pd(PPh3)4‐catalyzed C?F bond alkynylation of tetrasubstituted gem‐difluoroalkenes with terminal alkynes has been developed. This method gives access to a great variety of conjugated monofluoroenynes bearing a tetrasubstituted alkene moiety with well‐defined stereochemistry. Chelation‐assisted oxidative addition of Pd to the C?F bond is proposed to account for the high level of stereocontrol. An X‐ray crystal structure of a key monofluorovinyl PdII intermediate has been obtained for the first time as evidence for the proposed mechanism. 相似文献
6.
Elaine Tsui Anthony J. Metrano Yuto Tsuchiya Robert R. Knowles 《Angewandte Chemie (International ed. in English)》2020,59(29):11845-11849
We report a catalytic, light‐driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible‐light irradiation in the presence of an IrIII‐based photoredox catalyst, a Brønsted base catalyst, and a hydrogen‐atom transfer (HAT) co‐catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O?H bonds through a proton‐coupled electron‐transfer mechanism. This method exhibits a broad substrate scope and high functional‐group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented. 相似文献
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9.
Samit Mandal J Gerl H Geissel K Hauschild M Hellström Z Janas I Kojouharov Y Kopatch RC Lemmon P Mayet Z Podolyak PH Regan H Schaffner C Schlegel J Simpson HJ Wollersheim 《Pramana》2001,57(1):161-164
Feasibility of gamma-ray spectroscopy at relativistic energies with exotic heavy-ions and new generation of germanium detectors
(segmented Clover) is discussed. An experiment with such detector array and radioactive is discussed. 相似文献
10.