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961.
962.
Linyong Wang Meng Ye Lei Wang Wenzeng Duan Chun Song Yudao Ma 《Tetrahedron: Asymmetry》2017,28(1):54-61
Fluorine-substituted [2.2]paracyclophane-based carbene precursors have been successfully synthesized and applied to copper-catalyzed asymmetric β-boration of α,β-unsaturated ketones. Fluorination of the planar chiral carbenes has a beneficial impact on the catalytic performance of the relevant complexes. A variety of chiral β-boryl ketones were obtained in excellent yields (up to 99%) and with high enantioselectivities (up to 99% ee). 相似文献
963.
Lei Wang Ruiquan Liu Cong Lv Junjun Ou Feng Liu Shangzhong Liu Min Wang Jiangchun Zhong 《Tetrahedron: Asymmetry》2013,24(4):173-177
Six optically active α-hydroxyl-β,γ-unsaturated acid esters 1a to 1f were synthesised, and they are significant moieties of the cerebrosides. The chiral intermediate alkynol 4 prepared by catalytic asymmetric addition had 99% ee, and which was converted into the target compounds 1a to 1f with high enantiomeric purity. 相似文献
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965.
A novel long wavelength photodetector with dual-wavelength spectral response is designed and fabricated using a step-shaped Fabry-Prot (F-P) filter structure.The step-shaped GaAs/AlGaAs distributed Bragg reflectors and the InP PIN photodetector are grown on a GaAs substrate using low pressure metal organic chemical vapor deposition.High quality GaAs/InP heteroepitaxy is realized by employing a thin low temperature buffer layer.The photodetector structure is optimized by theoretical simulation.This device has a dual-peak distance of 19 nm (1 558 and 1 577 nm).The 3-dB bandwidth of 16 GHz is simultaneously obtained with peak quantum efficiencies of 8.5% and 8.6% around 1 558 and 1 577 nm,respectively. 相似文献
966.
High-Molecular-Weight Polynucleotides by Transferase-Catalyzed Living Chain-Growth Polycondensation 下载免费PDF全文
Dr. Lei Tang Luis A. Navarro Jr. Prof. Ashutosh Chilkoti Prof. Stefan Zauscher 《Angewandte Chemie (International ed. in English)》2017,56(24):6778-6782
We present terminal deoxynucleotidyl transferase-catalyzed enzymatic polymerization (TcEP) for the template-free synthesis of high-molecular-weight, single-stranded DNA (ssDNA) and demonstrate that it proceeds by a living chain-growth polycondensation mechanism. We show that the molecular weight of the reaction products is nearly monodisperse, and can be manipulated by the feed ratio of nucleotide (monomer) to oligonucleotide (initiator), as typically observed for living polymerization reactions. Understanding the synthesis mechanism and the reaction kinetics enables the rational, template-free synthesis of ssDNA that can be used for a range of biomedical and nanotechnology applications. 相似文献
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968.
969.
Lei Peng Fu-Min ZhangBing-Miao Yang Xiao-Bo ZhangWen-Xing Liu Shu-Yu ZhangYong-Qiang Tu 《Tetrahedron letters》2013
The total synthesis of isomer of didemnaketal A was achieved in 26 steps. The position of esters is switched at C7 and C8 with respect to their proposed position in natural didemnaketal A, which shows potent anti-HIV activity but so far has not been synthesized in the laboratory. Structural analysis of synthetic isomer of didemnaketal A indicates that the esters at C7 and C8 are correctly assigned, suggesting that the problems for the structural reassignment of natural didemnaketal A lie elsewhere. 相似文献
970.