Article
Chemistry, Multidisciplinary
Minghui Zhu, Peixin Wang, Qinglong Zhang, Wenjun Tang, Weiwei Zi
Summary: The aldol reaction is an important and versatile transformation in organic synthesis, but achieving stereoselectivity for the formation of diastereomeric products is challenging. In this study, a new catalytic system was developed to overcome the selectivity limitations of the reaction. Computational studies provided insights into the reaction mechanism and stereochemistry of the catalytic system.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Paul Zebrowski, Uwe Monkowius, Mario Waser
Summary: We report a two-step approach for the enantioselective synthesis of novel chiral δ-lactams. The protocol involves an asymmetric α-allylation of activated aryl esters followed by an acid-mediated lactam formation. The method provides highly enantioselective and reasonably high-yielding products, which can be further utilized via transformations of the exocyclic double bond.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Qingqing Luo, Zhou Tian, Jie Tang, Jie Wang, Yin Tian, Cheng Peng, Gu Zhan, Bo Han
Summary: The study focuses on the design of bifunctional 4-pyrrolidinopyridines as Lewis base catalysts, which exhibited excellent efficiency and stereoselectivity in asymmetric cycloaddition reactions. The research provides strong support for the construction of chiral spiropyrazolone derivatives.
Article
Chemistry, Organic
Lotte Stockhammer, Maximilian Radetzky, Syeda Sadia Khatoon, Matthias Bechmann, Mario Waser
Summary: A two-step protocol for the asymmetric synthesis of novel chiral benzofused ε-lactones starting from O-protected hydroxymethyl-para-quinone methides and activated aryl esters is reported. The use of chiral isothiourea Lewis base catalysts allows the obtaining of a broad variety of differently substituted products with high levels of enantioselectivities.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Nils Ansmann, Deborah Hartmann, Sonja Sailer, Philipp Erdmann, Rezisha Maskey, Marcel Schorpp, Lutz Greb
Summary: In this study, hypercoordinated silicon anions were characterized using a new donor-free polymeric form of Lewis superacidic bis(perchlorocatecholato)silane 1. The results provide insights into the role of silicon hypercoordination in synthesis and catalysis, and suggest pronounced substrate activation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Xu Chen, Zhiwei Qiao, Bang Hou, Hong Jiang, Wei Gong, Jinqiao Dong, Hai-Yang Li, Yong Cui, Yan Liu
Summary: Metal-organic frameworks (MOFs) have shown great potential in heterogeneous catalysis, and the enantioselectivities of chiral MOF (CMOF) catalysts can be significantly enhanced by designing metals and ligands, resulting in improved chiral catalytic reactions.
Article
Chemistry, Organic
Ye Wang, Lei Zheng, Xiaodong Shi, Yunfeng Chen
Summary: In this study, successful 1,3-difunctionalization of beta-alkylsubstituted nitroalkenes was achieved through a synergistic Lewis base catalysis and TBHP radical oxidation, yielding vinylic alkoxyamines in good to excellent yields. This work further extends the general synthetic application of beta-alkyl nitroalkenes.
Article
Chemistry, Multidisciplinary
Qiang Wang, Tomas Nilsson, Lars Eriksson, Kalman J. Szabo
Summary: The reported method allows for the synthesis of densely functionalized chiral allyl compounds with high stereo-, diastereo- and site-selectivity based on selenium-catalyzed sulfenofunctionalization of chiral alpha-CF3 allylboronic acids.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Polymer Science
Susanne M. Fischer, Viktor Schallert, Johanna M. Uher, Christian Slugovc
Summary: In this study, we propose a method for preparing crosslinked polymers from off-stoichiometric oxa-Michael formulations, by a self-limiting base catalyzed reaction between difunctional Michael acceptors and substoichiometric amounts of diols, followed by anionic polymerization of the remaining vinyl groups. The properties of the resulting polymers can be easily tuned by varying the amount of diols.
Article
Chemistry, Physical
Qinyi Li, Xinmin Liu, Weiyu Shi
Summary: This study confirms that the strong electric field and orbital asymmetric hybridization at charged clay surface substantially enhance Lewis acid-base reactions between Cu2+, Ca2+, Mg2+ and surface O. Infrared spectral analyses reveal changes in reaction intensity, highlighting the significance of these factors in clay catalyst design.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Multidisciplinary
Ruizhi Guo, Ziqi Liu, Xiaodan Zhao
Summary: This study presents a convenient and efficient method to construct valuable P-chirogenic compounds through chiral selenide-catalyzed enantioselective electrophilic aromatic halogenation. The new chiral bifunctional selenide catalyst successfully converted various bis(2-hydroxyaryl) aryl phosphine oxides into chlorinated and brominated P-chirogenic compounds with good enantioselectivities. By adjusting the catalyst and solvent, the method could also prepare chiral alkyl diaryl phosphine oxides and diaryl phosphinates.
Article
Chemistry, Physical
Zheng-Wang Qu, Hui Zhu, Stefan Grimme
Summary: The study on catalytic aromatic chlorination using N-chlorosuccinimides under mild conditions has revealed a novel catalytic mechanism and highlighted the potential role of O=SMe(2) as efficient Cl(+) and H(+) shuttles in the reaction. These mechanistic insights can aid in the rational design of novel dual functional halonium transfer catalysts.
Article
Chemistry, Multidisciplinary
Qian Wang, Yinggao Meng, Lulu Wu, Er-Qing Li
Summary: Metal/nucleophilic Lewis base dual catalysis has been recognized as a reliable and promising strategy for finishing ideal organic synthesis. This new strategy expands the synthetic utility of chemical transformations by leveraging additional activation modes and has made considerable progress in the synthesis of a wide range of heterocyclic and biologically active compounds. In this review, the comprehensive and updated advances of metal/nucleophilic Lewis base dual catalytic annulation reactions are described, along with the highlighting of the related mechanism and application in natural product total synthesis.
CHINESE CHEMICAL LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Simon Cromwell, Randy Sutio, Changhe Zhang, Georgina K. Such, David W. Lupton
Summary: In this study, a reaction cascade involving the addition of C1-pyridinium enolate to thiocarbonyl compounds was reported, leading to the synthesis of a range of dihydrothiophenes and dihydrothiopyrans. Mechanistic investigations and experimental evidence supported the involvement of an activated acid intermediate and turnover limiting cyclization in the reaction pathway, with subsequent formation of β-thiolactone regenerating the catalyst.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Yasuyuki Matsushima, Shunsuke Fukuda, Yusuke Kobayashi, Hiroyasu Nezu, Kosuke Nakashima, Shin-ichi Hirashima, Tsuyoshi Miura
Summary: High yields and excellent enantioselectivities (up to 92% ee) of phthalide derivatives were achieved by using a N,N-dibenzyl diaminomethylenemalononitrile organocatalyst in the asymmetric 5-exo bromolactonization of stilbene-type carboxylic acids. This is the first report demonstrating the successful synthesis of highly optically pure phthalide derivatives as the main product using the asymmetric 5-exo bromolactonization of stilbene-type carboxylic acids with various substituents.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Jun Cheng Er, Cheryl Leong, Chai Lean Teoh, Qiang Yuan, Paolomi Merchant, Matthew Dunn, David Sulzer, Dalibor Sames, Akshay Bhinge, Dongyoon Kim, Seong-Min Kim, Myung-Han Yoon, Lawrence W. Stanton, Shawn H. Je, Seong-Wook Yun, Young-Tae Chang
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2015)
Article
Chemistry, Multidisciplinary
Lu Wang, Lin Yuan, Xian Zeng, Juanjuan Peng, Yong Ni, Jun Cheng Er, Wang Xu, Bikram Keshari Agrawalla, Dongdong Su, Beomsue Kim, Young-Tae Chang
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2016)
Article
Chemistry, Multidisciplinary
Liyun Zhang, Jun Cheng Er, Xin Li, Jie Heng, Animesh Samanta, Young-Tae Chang, Chi-Lik Ken Lee
CHEMICAL COMMUNICATIONS
(2015)
Article
Chemistry, Multidisciplinary
Juanjuan Peng, Wang Xu, Chai Lean Teoh, Sanyang Han, Beomsue Kim, Animesh Samanta, Jun Cheng Er, Lu Wang, Lin Yuan, Xiaogang Liu, Young-Tae Chang
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2015)
Article
Chemistry, Multidisciplinary
Liyun Zhang, Jun Cheng Er, Hao Jiang, Xin Li, Zhaofeng Luo, Thomas Ramezani, Yi Feng, Mui Kee Tang, Young-Tae Chang, Marc Vendrell
CHEMICAL COMMUNICATIONS
(2016)
Article
Chemistry, Analytical
Liyun Zhang, Jun Cheng Er, Wang Xu, Xian Qin, Animesh Samanta, Santanu Jana, Chi-Lik Ken Lee, Young-Tae Chang
ANALYTICA CHIMICA ACTA
(2014)
Review
Chemistry, Medicinal
Chong Kiat Tan, Wesley Zongrong Yu, Ying-Yeung Yeung
Article
Multidisciplinary Sciences
Liyun Zhang, Jun Cheng Er, Krishna Kanta Ghosh, Wan Jun Chung, Jaeduk Yoo, Wang Xu, Wei Zhao, Anh Tuan Phan, Young-Tae Chang
SCIENTIFIC REPORTS
(2014)
Article
Biochemistry & Molecular Biology
Sung-Jin Park, Queenie Tan Shu Woon, Jun Cheng Er, Bernice H. Wong, Xiao Liu, Nam-Young Kang, Veluchamy A. Barathi, David L. Silver, Young-Tae Chang
Summary: The retina, part of the CNS, includes interneurons and sensory neurons such as photoreceptor cells. Retinitis pigmentosa (RP) is an inherited disease characterized by photoreceptor degeneration. A fluorescent probe NeuA was developed to detect retinal neuronal cells and distinguish healthy from RP retinas, showing potential as a preclinical tool for detecting RP.
Article
Food Science & Technology
Patrick Gan, Jun Cheng Er, Kenneth Chow, Benjamin Er, Joanne Sheot Harn Chan, Angela Li, Kyaw Thu Aung
Summary: This study examines the relationship between consumption of processed foods and sociodemographic factors among Singapore residents. The findings suggest that age, gender, ethnicity, housing, and health status all contribute to differences in processed food consumption, with ethnicity being the key factor driving the variation.
Article
Food Science & Technology
Sri Harminda Pahm Hartantyo, Renuka Selvaraj, Jiaying Ho, Jia Quan Oh, Jun Cheng Er, Angela Li, Kyaw Thu Aung
Summary: We conducted a survey on caterers with and without past hygiene violations to investigate their staffing, food safety practices, and correlations with microbial counts in food and the processing environment. The study found that past infringements did not have a negative impact on the current execution of food safety measures or the microbial quality of food. Instead of imposing stricter regulations on errant operators, alternative efforts to enhance food safety and their policy implications are discussed.
Article
Food Science & Technology
Wesley Zongrong Yu, Ping Shen, Ignatius Lim, Raymond Rong Sheng Shi, Miaohua Cai, Yee Soon Chin, Ai Jin Tay, Wei Min Ang, Jun Cheng Er, Geraldine Songlen Lim, Yuansheng Wu, Angela Li, Kyaw Thu Aung, Sheot Harn Chan
Summary: This study examined the impact of 'snackification' on Singaporean diets and the resulting increase in acrylamide exposure. Acrylamide levels in commonly consumed foods were measured using LC-MS/MS. High concentrations of acrylamide were found in vegetables cooked at high temperatures and potato-based crackers and chips. The estimated dietary exposure for Singapore's population exceeded the safe threshold, indicating a potential health concern. These findings emphasize the need for industry practices and consumer advisories to reduce acrylamide exposure from all types of food.
Article
Radiology, Nuclear Medicine & Medical Imaging
Chai Lean Teoh, Jun Cheng Er, Parag Mukherjee, Young-Tae Chang
Article
Chemistry, Organic
Geeta Devi Yadav, Pooja Chaudhary, Balaram Pani, Surendra Singh
Summary: Chiral transition metal complexes with privileged ligands are efficient catalysts for various asymmetric organic transformations. Transition metal complexes of C1-symmetric pyrrolidine-based ligands have been widely used in asymmetric organic reactions. However, a comprehensive review article on the transition metal complexes of chiral C1-symmetric pyrrolidine-based ligands derived from (L)-proline has not been published.
TETRAHEDRON LETTERS
(2024)
