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Nickel-Catalyzed Regio-and Stereoselective Defluorinative Arylation of gem-Difluorinated Cyclopropanes

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Chinese Journal of Chemistry 2024年第8期42卷 823-828页

作者： Shutao Qi Yunkai Hua Liangkai Pan Junfeng Yang Junliang Zhang Department of Chemistry Fudan University2005 Songhu RoadShanghai200438 China Fudan Zhangjiang Institute Shanghai201203 China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHenan 453007China

Comprehensive Summary,Herein,we report nickel-catalyzed cross-coupling of gem-difluorinated cyclopropanes with boronic acids,providing the corresponding arylated 2-fluoroallylic scaffolds.This approach used commercially available phosphine ligand Xantphos to obtain monofluorinated alkenes with high regioselectivity and Z-stereoselectivity.Mechanistic studies proposed a Ni(II)-fluoroallyl pathway and excluded the radical pathway.

关键词： Nickel Monofluoroolefin Cyclopropane Regioselectivity stereoselectivity C-C coupling Cross-coupling Synthetic methods

Concise Synthesis of Lactococcus garvieae Lipoteichoic Acids Through an Additive-Modulated Preactivation Protocol and the Immunological Studies

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CCS Chemistry 2024年第2期6卷 403-414页

作者： Tianlu Li Tong Li Yue Yang Haoru Zhuang Jianwu Lv Ning Zhou Miaomiao Zhang Fengshan Wang Yiqun Geng Richard R.Schmidt Peng Peng National Glycoengineering Research Center Shandong Key Laboratory of Carbohydrate Chemistry and GlycobiologyNMPA Key Laboratory for Quality Research and Evaluation of Carbohydrate Based MedicineShandong UniversityQingdao 266237 State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050 Department of Chemistry University of KonstanzD-78457 Konstanz

Lipoteichoic acids(LTAs)are macroamphiphiles composed of alditol,lipid,phosphate,and carbohydrate units.Due to their inherent complexity,it is a severe challenge to access LTAs with structural integrity from natural sources for biological or immunological evaluation.Here,we describe the first total synthesis of Lactococcus garvieae LTA(type II LTA),containing five distinct 1,2-cis gluco/galactopyranosidic linkages,via a novel additive-modulated O-glycosyl trichloroacetimidate preactivation glycosidation strategy.This strategy features(1)high glycosidation yields and excellent 1,2-cis stereoselectivities independent of the donor anomeric configuration,(2)common and inexpensive reagents as promoters and additives,(3)application to standard glycosyl imidate donors without resorting to participating protection,and(4)general application to reactive and less reactive glycosyl acceptors.Thus,via the precise stereocontrolled construction of three galactopyranosidic and two glucopyranosidic bonds on a multigram scale,a series of structurally well-defined LTA molecules were successfully assembled.Immunological evaluation of these type II synthetic LTAs showed a structure–activity relationship in the stimulation of a proinflammatory response.

关键词： 1,2-cis glycosidation stereoselectivity lipoteichoic acid total synthesis additive-modulated trichloroacetimidate glycosidation immune response

Highly efficient synthesis of(R)-1,3-butanediol via anti-Prelog reduction of 4-hydroxy-2-butanone with absolute stereoselectivity by a newly isolated Pichia kudriavzevii

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2160-2166页

作者： Han Zu Hui Zhang Anwen Fan Jie Gu Yao Nie Pengjie Luo Yan Xu School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education Jiangnan UniversityWuxi 214122China State Key Laboratory of Food Science and Technology Jiangnan UniversityWuxi 214122China China National Center for Food Safety Risk Assessment NHC Key Laboratory of Food Safety Risk AssessmentBeijing 100022China

(R)-1,3-butanediol is an important pharmaceutical intermediate, and the synthesis of(R)-1,3-butanediol using green biological methods has recently been of interest for industrial application. Here, a novel strain QC-1 that efficiently transforms 4-hydroxy-2-butanone to(R)-1,3-butanediol was isolated from soil samples. Based on morphological, physiological, and biochemical tests and 5.8 S-internal transcribed spacer sequencing, the strain was identified as Pichia kudriavzevii QC-1. The reaction conditions were optimized to 35 ℃, pH 8.0, rotation speed 200 rpm, and 6:5 mass ratio of glucose to 4-hydroxy-2-butanone. Evaluation of the effects of 4-hydroxy-2-butanone concentrations on yield and cell survival rate showed that 85.60 g·L^-1 product accumulated, with an enantiomeric excess of more than 99%, when 30 g·L^-14-hydroxy-2-butanone was added at 0, 10, and 30 h in a 3-L bioreactor. Thus, strain QC-1 showed excellent catalytic activity and stereoselectivity for the synthesis of(R)-1,3-butanediol from 4-hydroxy-2-butanone.

关键词： Asymmetric reduction stereoselectivity (R)-1 3-butanediol 4-Hydroxy-2-butanone Whole-cell catalysis

From Reactivity and Regioselectivity to stereoselectivity: An Odyssey of Designing PIP Amine and Related Directing Groups for C-H Activation

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Chinese Journal of Chemistry 2019年第7期37卷 647-656页

作者： Qi Zhang Bing-Feng Shi Department of Chemistry Zhejiang University Hangzhou Zhejiang 310027 China

What is the most favorite and original chemistry developed in your research group? Developing PIP amine for regio-and enantioselective methylene C-H activation. How do you get into this specific field? Could you pleas... 详细信息

关键词： Regioselectivity stereoselectivity

Theoretical investigation of the stereoselectivity of some Diels-Alder reactions involving cyclopentadiene

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Chinese Chemical Letters 2008年第9期19卷 1135-1138页

作者： Dong Xia Zhao Zhen Zhen Xu Zhong Zhi Yang College of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116029 China

The stereoselectivity of some Diels-Alder reactions was investigated by means of ABEEM-oTr model. Combined with local hard-soft and acid-base （HSAB） principle, we made reasonable explanation by calculating local sof... 详细信息

关键词： ABEEM-σπ model Diels--Alder reaction stereoselectivity Local softness

Promotion Mechanism of H2O for stereoselectivity in Pd(Ⅱ)-catalyzed C—H Aryiation of Diarylphosphinamides with Arylboronic Acids

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Chemical Research in Chinese Universities 2020年第5期36卷 843-846页

作者： CAI Yanchun JIAO Long QIU Xuepcng DU Zhijun Polymer Composites Engineering laboratory Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022P.R.China

On the basis of a series of control experiments and nuclear magnetic resonance analyses,it is discovered that Boc-protected amino acid ligand coordinated to Pd center is partly replaced by N,N-dimethylformamide,and H2O can inhibit coordination of N,N-dimethylformamide to Pd center.The novel action mechanism perfectly explains H2O promotion for stereoselectivity in Pd(II)-catalyzed C—H aryiation of diarylphosphinamides with arylboronic acids.

关键词： C-H activation stereoselectivity Water Ligand exchange

STUDIES ON THE stereoselectivity AND SUBSTITUTED GROUPS OF (+)-CAMPHOR DERIVATIVES

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Science China Chemistry 1991年第4期34卷 385-393页

作者：郭鹏刘桂兰蒋耀忠周忠远 Chengdu Institute of Organic Chemistry Academia Sinica Chengdu 610015 PRC Chengdu Center of Analysis and Measurement Academia Sinica Chengdu 610015 PRC

From (+)- camphor, six new (+)-camphor derivatives were synthesized. According tothe structure and chemical properties of the derivatives, the relation between the substitutedgroups and the stereoselectivity of alkylations and reduction was examined. It is found thatthe chemical shift of protons of C(8), C(9) methyl groups and chemical properties of carbonylO(2) are associated with the substituted groups.

关键词： (+)-camphor derivatives configuration stereoselectivity

Chemical approaches for the stereocontrolled synthesis of 1,2-cis-β-D-rhamnosides

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Chinese Journal of Natural Medicines 2023年第12期21卷 886-901页

作者： CAI Juntao YUAN Xin KONG Yuanfang HU Yulong LI Jieming JIANG Shiqing DONG Chunhong DING Kan Henan Polysaccharide Research Center Henan Key Laboratory of Chinese Medicine for Polysaccharides and Drugs ResearchAcademy of Chinese Medical SciencesHenan University of Chinese MedicineZhengzhou 450046China College of Pharmacy Henan University of Chinese MedicineZhengzhou 450046China Department of Oncology The First Affiliated Hospital of Henan University of Chinese MedicineZhengzhou 450000China Carbohydrate-Based Drug Research Center CAS Key Laboratory of Receptor ResearchState Key Laboratory of Drug ResearchShanghai Institute of Materia MedicaChinese Academy of SciencesShanghai 201203China

In carbohydrate chemistry,the stereoselective synthesis of 1,2-cis-glycosides remains a formidable challenge.This complexity is comparable to the synthesis of 1,2-cis-β-D-mannosides,primarily due to the adverse anomeric andΔ-2 effects.Over the past decades,to attainβ-stereoselectivity in D-rhamnosylation,researchers have devised numerous direct and indirect methodologies,including the hydrogen-bond-mediated aglycone delivery(HAD)method,the synthesis ofβ-D-mannoside paired with C6 deoxygenation,and the combined approach of 1,2-trans-glycosylation and C2 epimerization.This review elaborates on the advancements inβ-Drhamnosylation and its implications for the total synthesis of tiacumicin B and other physiologically relevant glycans.

关键词： Carbohydrate Glycosylation 1,2-cis-Glycoside stereoselectivity Total synthesis β-Rhamnoside

Enantioselective Reductive Cross-Coupling of Aryl/Alkenyl Bromides with Benzylic Chlorides via Photoredox/Biimidazoline Nickel Dual Catalysis

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Chinese Journal of Chemistry 2022年第9期40卷 1033-1038页

作者： Tongtong Li Xiaokai Cheng Jiamin Lu Huifeng Wang Qun Fang Zhan Lu Department of Chemistry Zhejiang University 866 Yuhangtang roadHangzhouZhejiang 310058China College of Chemistry ZhengzhouUniversityZhengzhouHenan 450001China Hangzhou Innovation Center Zhejang UniversityHangzhouZhejiang 311200China

The asymmetric reductive arylation and alkenylation of benzylic chloride under photoredox/nickel dual catalysis using chiral bimidazoline(Bilm)ligand is reported to access 1,1-diaryl alkanes and aryl allylic compounds with good yield as well as stereo-and enantioselectivities.This protocol uses more commercially available and less expensive C(sp^(2))-Br as the electrophile coupling partner.A primary result using alkenyl chloride and alkyl chloride is also reported.Various functional groups are tolerated and the applications of this method are investigated by late-stage functionalization and gram-scale reaction.

关键词： Cross-coupling Photocatalysis Enantioselectivity stereoselectivity Bimidazoline