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991.
Fangyuan Zhou Lesong Li Kao Lin Feng Zhang Prof. Dr. Guo-Jun Deng Dr. Hang Gong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(19):4246-4250
The radical–radical coupling reaction is an important synthetic strategy. In this study, the iron-catalyzed radical–radical cross-coupling reaction based on the decarboxylation of keto acids and decarbonylation of aliphatic aldehydes to obtain valuable aryl ketones is reported for the first time. Remarkably, when tertiary aldehydes were used as carbonyl sources, ketone esters were selectively obtained instead of ketones. The gram-scale preparation of aryl ketone through this strategy was easily achieved by using only 3 mol % of the iron catalyst. As a proof-of-concept, the bioactive molecule flurprimidol was synthesized in two steps by using this strategy. 相似文献
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System modeling and parameter estimation are basic for system analysis and controller design. This paper considers the parameter identification problem of a Hammerstein multi-input multi-output (H-MIMO) system. In order to avoid the product terms in the identification model, we derive a pseudo-linear identification model of the H-MIMO system through separating a key term from the output equation of the system and present a hierarchical generalized least squares (LS) algorithm for estimating the parameters of the system. Moreover, we present a new LS algorithm to reduce the computational burden. The proposed algorithms are simple in principle and can achieve a higher computational efficiency than the over-parameterization-based LS estimation algorithm. Finally, we test the proposed algorithms by the simulation example and show their effectiveness. 相似文献
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Yu‐Feng Liang Ning Jiao 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(2):558-562
A transition‐metal‐free Cs2CO3‐catalyzed α‐hydroxylation of carbonyl compounds with O2 as the oxygen source is described. This reaction provides an efficient approach to tertiary α‐hydroxycarbonyl compounds, which are highly valued chemicals and widely used in the chemical and pharmaceutical industry. The simple conditions and the use of molecular oxygen as both the oxidant and the oxygen source make this protocol very environmentally friendly and practical. This transformation is highly efficient and highly selective for tertiary C(sp3) H bond cleavage. 相似文献
1000.
Shu‐Ting Wu Zhen‐Wen Cai Qiao‐Yan Ye Chen‐Hao Weng Xi‐He Huang Xiao‐Lin Hu Chang‐Cang Huang Nai‐Feng Zhuang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(47):13074-13078
Circular dichroism is known to be the feature of a chiral agent which has inspired scientist to study the interesting phenomena of circularly polarized light (CPL) modulated molecular chirality. Although several organic molecules or assemblies have been found to be CPL‐responsive, the influence of CPL on the assembly of chiral coordination compounds remains unknown. Herein, a chiral coordination polymer, which is constructed from achiral agents, was used to study the CPL‐induced enantioselective synthesis. By irradiation with either left‐handed or right‐handed CPL during the reaction and crystallization, enantiomeric excesses of the crystalline product were obtained. Left‐handed CPL resulted in crystals with a left‐handed helical structure, and right‐handed CPL led to crystals with a right‐handed helical structure. It is exciting that the absolute asymmetric synthesis of a chiral coordination polymer could be enantioselective when using CPL, and provides a strategy for the control of the chirality of chiral coordination polymers. 相似文献