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Synthesis of chiral phosphine derivatives through a copper（I）-catalyzed desymmetric SNAr reaction

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Science China Chemistry 2025年

作者： shuai Zhang Pei-Zhi liu yan-Bo li Qi Zhang Jun-Zhao xiao Yi-Fan Wang tian-Yu Wei Jia-Wei Jiang Ye Wang Qian Peng liang Yin Key Laboratory of Fluorine and Nitrogen Chemistry and Advanced Materials Shanghai Institute of Organic Chemistry University of Chinese Academy of Sciences Chinese Academy of Sciences State Key Laboratory of Elemento-Organic Chemistry and tianjin Key Laboratory of Biosensing and Molecular Recognition College of Chemistry Frontiers Science Center for New Organic Matter Nankai University Haihe Laboratory of Sustainable Chemical Transformations

Axially chiral phosphines are a class of extremely important ligands in asymmetric catalysis. Herein, an unprecedented copper（I）-catalyzed asymmetric SNAr reaction with HP（S）R2is uncovered, which delivers a series of axially chiral phosphine derivatives in high yields with excellent enantioselectivity. Furthermore, the diastereoselective reaction with the kinetic resolution of racemic HP（S）ArR proceeds smoothly, providing the products with moderate diastereoselectivity and excellent enantioselectivity. Control experiments indicate that HP（S）Ph2is much more active than HPPh2and HP（O）Ph2as the pronucleophile in the present reaction. It is found that the SNAr reaction （the first SNAr） proceeds in a desymmetric manner, providing the desired chiral products while a continued SNAr reaction （the second SNAr） slightly occurs in a kinetic resolution manner in the present catalytic system, which enhances the ee of the desired chiral products. DFTcalculations support a concerted reaction pathway rather than a step-wise mechanism. Finally, axially chiral olefin-phosphines produced by the present method work as suitable ligands in Pdcatalyzed asymmetric allylic substitution with C-, N-, and O-nucleophiles and Rh-catalyzed asymmetric addition of arylboronic acid to benzil.

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Epigenetics in the modern era of crop improvements

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Science China life Sciences 2025年

作者： yan Xue xiaofeng Cao Xiangsong Chen Xian Deng Xingwang Deng Yong Ding Aiwu Dong Chengguo Duan xiaofeng Fang Lei Gong Zhizhong Gong xiaofeng Gu Chongsheng He Hang He Shengbo He Xinjian He yan He Yuehui He Guifang Jia Danhua Jiang Jianjun Jiang Jinsheng Lai Zhaobo Lang Chenlong li Qing li Xingwang li Bao liu Bing liu xiao Luo Yijun Qi Weiqiang Qian Guodong Ren Qingxin Song Xianwei Song Zhixi tian Jiawei Wang Yuan Wang liang Wu Zhe Wu Rui Xia Jun xiao lin Xu Zhengyi Xu Wenhao yan Hongchun yang Jixian Zhai Yijing Zhang Yusheng Zhao Xuehua Zhong Daoxiu Zhou Ming Zhou Yue Zhou Bo Zhu Jiankang Zhu Qikun liu College of life Sciences Institute of Life Science and Green Development Hebei University Biotechnology Research Institute Chinese Academy of Agricultural Sciences College of Biology Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation Hunan Engineering and Technology Research Center of Hybrid Rapeseed Hunan University Institute of Advanced Agricultural Sciences School of Advanced Agricultural Sciences Peking University State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources Guangdong Laboratory for Lingnan Modern Agriculture South China Agricultural University National Institute of Biological Sciences Key Laboratory of Seed Innovation Institute of Genetics and Developmental Biology Chinese Academy of Sciences School of Advanced Agricultural Sciences Peking-Tsinghua Center for Life Sciences Peking University Synthetic and Functional Biomolecules Center Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education College of Chemistry and Molecular Engineering Peking University Key Laboratory of Seed Innovation State Key Laboratory of Plant Genomics and National Center for Plant Gene Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences State Key Laboratory of Wheat Improvement Peking University Institute of Advanced Agricultural Sciences Shandong Laboratory of Advanced Agricultural Sciences in Weifang State Key Laboratory of Crop Stress Adaptation and Improvement School of Life Sciences Henan University State Key Laboratory of Maize Bio-breeding National Maize Improvement Center Department of Plant Genetics and Breeding China Agricultural University Frontiers Science Center for Molecular Design Breeding China Agricultural University Center for Crop Functional Genomics and Molecular Breeding China Agricultural University Sanya Institute of China Agricultural University Hainan Yazhou Bay Seed Laboratory Institute of Advan

Epigenetic mechanisms are integral to plant growth, development, and adaptation to environmental stimuli. Over the past two decades,our comprehension of these complex regulatory processes has expanded remarkably, producing a substantial body of knowledge on both locus-specific mechanisms and genome-wide regulatory patterns. Studies initially grounded in the model plant Arabidopsis have been broadened to encompass a diverse array of crop species, revealing the multifaceted roles of epigenetics in physiological and agronomic traits. With recent technological advancements, epigenetic regulations at the single-cell level and at the large-scale population level are emerging as new focuses. This review offers an in-depth synthesis of the diverse epigenetic regulations, detailing the catalytic machinery and regulatory functions. It delves into the intricate interplay among various epigenetic elements and their collective influence on the modulation of crop traits. Furthermore, it examines recent breakthroughs in technologies for epigenetic modifications and their integration into strategies for crop improvement. The review underscores the transformative potential of epigenetic strategies in bolstering crop performance, advocating for the development of efficient tools to fully exploit the agricultural benefits of epigenetic insights.

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Diversity and conservation of Chinese wild begonias

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Plant Diversity 2018年第3期40卷 75-90页

作者： Daike tian yan xiao Yi tong Naifeng Fu Qingqing liu Chun li Shanghai Chenshan Plant Science Research Center of Chinese Academy of Sciences Shanghai Chenshan Botanical Garden Shanghai 201602 China Shanghai Key Laboratory of Plant Functional Genomics and Resources Shanghai 201602 China Lushan Forestry Bureau Ya'an 625600 Sichuan China

Begonia, one of the most diverse plant taxa and the fifth or sixth largest angiosperm genus, consists of over1800 accepted species. The number of species recognized within this genus has greatly increased over the past 20 years, rising from 80 to 200 species in China alone. Based on recent field surveys, the number of begonia species in China is predicted to be between 250 and 300. Given the large number of begonia species that still remain to be described, further taxonomical work is urgently required. This is especially true for Chinese Begonia, in which there is a huge diversity of habitat, habit, plant size, leaf type, flower and fruit morphology, and most species are narrowly distributed in isolated habitats that are subject to negative disturbances from climate change, as well as agricultural and industrial activities. Although the conservation status for the majority of species has been evaluated using the standards of the International Union for Conservation of Nature, the results don't represent the truth in many species, and also about11.5% of which are data-absent. In addition, illegal collection and over-harvesting of wild begonias for ornamental or medicinal use has increased due to the rapid development of internet commerce. Far more often than predicted, these species should be categorized as rare and endangered and require immediate protection. Ex situ conservation of Chinese begonias started in 1995 and over 60% of the total species have been so far introduced into cultivation by several major botanical gardens in China. However, only few research institutions, limited funds and human resources have been involved in Begonia conservation;moreover, no project has conducted reintroduction. Therefore, more conservation-based work remains to be done. Improved conservation of Chinese begonias in the future depends on further field survey, an improved understanding of population diversity, and integrative approaches, including in situ and ex situ conservat

关键词： Begonia Germplasm Diversity Conservation Taxonomic status China

On Characterization of Poisson Integrals of Schr?dinger Operators with Morrey Traces

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Acta Mathematica Sinica,English Series 2018年第4期34卷 787-800页

作者： liang SONG xiao xiao tian li Xin yan Department of Mathematics Sun Yat-sen University

Let L be a Schrodinger operator of the form L = -△ ＋ V acting on L2（Rn） where the nonnegative potential V belongs to the reverse Holder class Bq for some q _〉 n. In this article we will show that a function f∈ L2,λ（Rn）, 0 〈λ 〈 n, is the trace of the solution of Lu = -utt ＋ Lu = O, u（x, 0） = f（x）, where u satisfies a Carleson type condition sup t-λB xB,rB∫τB 0∫B（xB,τB）t{ u（x,t）}2dxdt≤C〈∞.Its proof heavily relies on investigate the intrinsic relationship between the classical Morrey spaces and the new Campanato spaces .L2,λL（Rn） associated to the operator L, i.e. Conversely, this Carleson type condition characterizes all the L-harmonic functions whose traces belong to the space L2,λ（Rn） for all 0 〈λ〈 n.

关键词： SchrSdinger operators Dirichlet problem Morrey spaces Campanato spaces Poissonsemigroup

An imported Genotype D Coxsackievirus B4 Strain Identified in tianjin,China

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Biomedical and Environmental Sciences 2022年第3期35卷 239-247页

作者： TAN Zhao lin LYU li Kun XIE tong li li li xiao yan tianjin Centers for Disease Control and Prevention Tianjin 300011China

Hand,foot,and mouth disease(HFMD)is an infectious disease caused by various enterovirus(EV)serotypes and occurs in infants and children across the *** mild symptoms of HFMD include fever and a maculopapular rash on th... 详细信息

关键词： fever enterovirus patients

Inversion analysis of the shear strength parameters for a high loess slope in the limit state

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Journal of Mountain Science 2021年第1期18卷 252-264页

作者： liN xiao-yan ZHANG lin-fan yanG Ze li Ping li tong-lu School of Earth Sciences and Engineering Xi'an Shiyou UniversityXi'an 710065China Shaanxi Key Laboratory of Petroleum Accumulation Geology Xi'an Shiyou UniversityXi'an 710065China School of Geological Engineering and Surveying Chang'an UniversityXi'an 710061China

It is difficult to obtain reliable shear strength parameters for the stability analysis and evaluation of high loess ***,this paper determines slope elements and physical parameter of 79 slopes with heights of[40,120]m based on the measured loess slopes in the Ganquan and tonghuang subregions of northern Shaanxi Province,*** the limit state of the loess slope(stability factor Fs is 1.0),a fitting equation for the slope height and width is ***,the model is developed by stability analysis software-SLOPE/W,and the comprehensive shear strength parameters corresponding to different slope heights of the high slope in the study area are obtained by inversion using the Morgenstern-Price *** results show that when the height of the slope increases,the cohesion c increases in the soil,and the internal friction angle j *** change is consistent with the characteristics reflected in the composition and physical properties of the slopes,and the comprehensive strength parametric curves are very similar between the Ganquan subregion and the tonghuang subregion.A landslide that occurred in Miaodian-zaitou of Jingyang County,Shaanxi Province,is selected to verify this inversion method,and the results show that the calculated shear strength parameters of the inversion are consistent with the measured value of the actual slope.

关键词： Loess High slope Shear strength Inversion SLOPE/W

Motion and Dynamic Responses of A Semisubmersible in Freak Waves

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China Ocean Engineering 2017年第6期31卷 754-763页

作者： li Xin DENG yan-fei li Lei tian Xin-liang li Jun State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China CIMC Offshore Co. Ltd. Shenzhen 518000 China

The present research aims at clarifying the effects of freak wave on the motion and dynamic responses of a semisubmersible. To reveal the effects of mooring stiffness, two mooring systems were employed in the model tests and time-domain simulations. The 6-DOF motion responses and mooring tensions have been measured and the 3- DOF motions of fairleads were calculated as well. From the time series, trajectories and statistics information, the interactions between the freak wave and the semisubmersible have been demonstrated and the effects of mooring stiffness have been identified. The shortage of numerical simulations based on 3D potential flow theory is presented. Results show that the freak wave is likely to cause large horizontal motions for soft mooring system and to result in extremely large mooring tensions for tight mooring system. Therefore, the freak wave is a real threat for the marine structure, which needs to be carefully considered at design stage.

关键词： motion response mooring tension semisubmersible freak wave mooring stiffness

The Southwest Indian Ocean Thermocline Dome in CMIP5 Models:Historical Simulation and Future Projection

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Advances in Atmospheric Sciences 2016年第4期33卷 489-503页

作者： xiao-tong ZHENG lihui GAO Gen li yan DU Key Laboratory of Physical Oceanography Ministry of Education and Key Laboratory of Ocean–Atmosphere Interaction and Climate in Universities of Shandong Ocean University of China Qingdao Collaborative Innovation Center of Marine Science and Technology Ocean University of China State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences

Using 20 models of the Coupled Model Intercomparison Project Phase 5 （CMIP5）, the simulation of the Southwest Indian Ocean （SWIO） thermocline dome is evaluated and its role in shaping the Indian Ocean Basin （IOB） mode following E1 Nifio investigated. In most of the CMIP5 models, due to an easterly wind bias along the equator, the simulated SWIO thermocline is too deep, which could further influence the amplitude of the interannual IOB mode. A model with a shallow （deep） thermocline dome tends to simulate a strong （weak） IOB mode, including key attributes such as the SWIO SST warming, antisymmetric pattern during boreal spring, and second North Indian Ocean warming during boreal summer. Under global warming, the thermocline dome deepens with the easterly wind trend along the equator in most of the models. However, the IOB amplitude does not follow such a change of the SWIO thermocline among the models; rather, it follows future changes in both ENSO forcing and local convection feedback, suggesting a decreasing effect of the deepening SWIO thermocline dome on the change in the IOB mode in the future.

关键词： SWIO thermocline dome Indian Ocean basin mode global warming CMIP5 ENSO

Achieving high carrier mobility and low lattice thermal conductivity in GeTe-based alloys by cationic/anionic co-doping

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Rare Metals 2024年第6期43卷 2784-2795页

作者： xiao-Qiang Wang xiao-Quan Hu Jun-yan lin Chu-Bin li xiao-tong Yu Qi-Yong Chen li-li Xi Qi-shuo yang Han li Ji-Ye Zhang shuan-Kui li Kai Guo School of Physics and Materials Science Guangzhou UniversityGuangzhou 510006China Research Center for Advanced Information Materials(CAIM) Huangpu Research&Graduate School of Guangzhou UniversitySino-Singapore Guangzhou Knowledge CityGuangzhou510555China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Materials Genome Institute Shanghai UniversityShanghai 200444China School of Mechanical and Mining Engineering University of QueenslandBrisbaneQLD 4072Australia Key Laboratory of Si-Based Information Materials&Devices and Integrated Circuits Design Department of Education of Guangdong ProvinceGuangzhou 510006China

TheⅣ-Ⅵcompound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric ***,pristine GeTe suffers from a high concentration of Ge vacancies,resulting in an excessively high hole concentration(>1×10^(21)cm^(-3)),which greatly limits its thermoelectric *** address this issue,CuBiTe_(2)alloying is introduced to increase the formation energy of Ge vacancies in GeTe,thereby inhibiting the high carrier *** carrier scattering caused by the electronegativity difference between different elements is suppressed due to the similar electronegativity of Cu and Ge atoms.A relatively high hole mobility is obtained,which ultimately leads to a high power ***,by introducing Se as an alloying element at the anionic site in GeTe,dense point defects with mass/strainfield fluctuations are *** contributes to the strengthening of phonon scattering,thereby reducing the lattice thermal conductivity from 1.44 W·m^(-1)·K^(-1)for pristine GeTe to 0.28 W·m^(-1)·K^(-1)for Ge_(0.95)Cu_(0.05)Bi_(0.05)Te_(0.9)Se_(0.15)compound at 623 K.

关键词： GeTe Carrier mobility CuBiTe_(2)alloying Lattice thermal conductivity Thermoelectric properties