Article
Chemistry, Organic
Killari Satyam, Jakkula Ramarao, Surisetti Suresh
Summary: The NHC-catalyzed intramolecular benzoin condensation-oxidation allows for the expedient synthesis of diverse cyclic 1,2-diketones incorporated in dibenzo-fused seven-membered heterocycles in good to excellent yields under ambient conditions. The transformation appears to proceed through the benzoin intermediate followed by aerobic oxidation.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Gargi Kundu, V. S. Ajithkumar, K. Vipin Raj, Kumar Vanka, Srinu Tothadi, Sakya S. Sen
Summary: In this study, we synthesized a 6-membered saturated NHC borane adduct and investigated its reactivity. The results showed that the adduct could undergo electrophilic halogenation to form NHC boryl iodides, which further reacted with various nucleophiles to yield novel boranes with different functional groups. Additionally, the adduct reacted with Br-2/H2O to produce a dihydroxyborenium cation.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Ricardo J. Alves, Laize Zaramello, Elvis N. Nishida, Frank H. Quina, Bruno S. Souza
Summary: In this study, we investigated the transient formation of N-heterocyclic carbenes (NHCs) in zwitterionic imidazolium sulfonate surfactants in a water environment. The formation of NHCs was accelerated above the critical micelle concentration, due to increased local concentration of hydroxide or deuteroxide ions. The rate of NHC formation could be controlled by the anions of added salts, which also affected the selectivity of anion binding to the micelle surface. The NHCs generated at the micelle surface promoted the selective oxidation of 4-nitrobenzaldehyde, demonstrating the importance of micellar microenvironment in controlling reactivity and selectivity in aqueous media.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Inorganic & Nuclear
Gargi Kundu, Ruchi Dixit, Srinu Tothadi, Kumar Vanka, Sakya S. Sen
Summary: The reaction of 6-SIDipp with different reagents has been studied, resulting in brominated products, adducts, and ring-expanded products.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Matthias D. Boehme, Lukas F. B. Wilm, Alexander Hepp, F. Ekkehardt Hahn
Summary: Oxidative addition reactions of the symmetric bis-NHC precursor 1 with [Pd(PPh3)4] resulted in the formation of dinuclear bis-pNHC complex, while unsymmetric compound 2(BF4) only underwent metallation at the 2-chlorobenzimidazolium site. Subsequent metallation of the remaining 2-chlorobenzimidazole moiety with [M(PPh3)4] (M=Pd, Pt) led to the formation of homobimetallic NHC/pNHC complex and heterobimetallic complex, demonstrating unique site-selective metallation of the bis-NHC precursor 2(BF4) through two consecutive oxidative additions.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Applied
Lakshmikanta Maity, Sahadev Barik, Raju Biswas, Ramalingam Natarajan, Joydev Dinda
Summary: In this study, the synthesis, structures, luminescent properties, and electrochemistry of gold(III)-N-heterocyclic carbene (NHC) complexes with 2,2'-bipyridine (bpy) or 1,10'-phenanthroline (phen) were investigated. The presence of NHC significantly enhanced the emission properties of the complexes.
APPLIED ORGANOMETALLIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Elvan Ustun, Neslihan Sahin, Cem Celik, Ugur Tutar, Namik Ozdemir, Nevin Gurbuz, Ismail Ozdemir
Summary: Microorganisms form biofilms that provide sheltered areas for host cell response in fields such as medicine, food, and pharmaceuticals, causing troubles. Inhibition of biofilm formation through hindering of quorum sensing could be a method for new generation antibiotics production. This study synthesized and characterized new benzimidazole type NHC precursors and evaluated their antimicrobial and biofilm formation inhibition activities. The complex molecules showed higher activity compared to the benzimidazole derivative ligands.
DALTON TRANSACTIONS
(2021)
Article
Chemistry, Multidisciplinary
Yunquan Man, Xiaojun Zeng, Bo Xu
Summary: We have developed an efficient N-heterocyclic carbene (NHC)-catalyzed thioesterification of aldehydes using N-thiosuccinimides as the thiolation reagent. This method allows easy access to highly functionalized thioesters and demonstrates good chemical yields and functional group tolerance.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Review
Chemistry, Multidisciplinary
Yang Li, Jian-Gang Yu, Li-Li Ma, Man Li, Yuan-Yuan An, Ying-Feng Han
Summary: N-heterocyclic carbene (NHC) ligands are widely used as carbon donors in supramolecular assemblies, with rapid growth in synthetic strategies and applications in molecular recognition, luminescent materials, and catalysis. Diverse selection of poly-NHC precursors and synthetic strategies are crucial for precise control of the synthesis of supramolecular architectures for different topological systems.
SCIENCE CHINA-CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Kajal Balayan, Himanshu Sharma, Kumar Vanka, Sapna Ravindranathan, Rajesh G. Gonnade, Sakya S. Sen
Summary: The combination of 6-SIDipp center dot AlH3 (1) and 5-IDipp leads to the expansion of 6-NHC ring, while the five-membered NHC remains unchanged. This phenomenon is further explained by DFT studies. Moreover, the substitution chemistry of compound 1 with TMSOTf and I-2 results in the replacement of a hydride by triflate or iodide ligands.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Nida Shahid, Rahul Kumar Singh, Navdeep Srivastava, Amrendra K. K. Singh
Summary: A series of Ru(III)-NHC complexes have been prepared through a base-free route. These air and moisture-stable complexes, which represent rare examples of paramagnetic Ru(III)-NHC complexes, were shown to be excellent metal precursors for the synthesis of new Ru(II)-NHC complexes. This work allows easy access to new Ru-NHC complexes for the study of new properties and novel applications.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Ashmita Singh, A. K. Narula
Summary: A facile method for the amidation of aldehydes by a cascade approach has been developed using NHC as the catalyst and NHS as the mediator. The method utilizes TBHP as the oxidant. Various substituted aldehydes reacted smoothly with NHS to form active esters, which were easily converted into amides. The drug moclobemide was successfully synthesized using this methodology to demonstrate its practical utility.
NEW JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Sebastien G. Guillet, Ishfaq Ibni Hashim, Marek Belis, Kristof Van Hecke, Catherine S. J. Cazin, Steven. P. Nolan
Summary: A simple synthetic method for synthesizing various [Rh(acac)(CO)(NHC)] complexes is presented. In situ infrared monitoring provides valuable information on the reaction mechanism, including the identification of a crucial intermediate. Understanding the reaction mechanism has led to the discovery of novel pathways to commonly used congeners.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Gianmarco Pisano, Catherine S. J. Cazin
Summary: A user-friendly and highly efficient mechanochemical strategy for the synthesis of well-defined, catalytically relevant N-heterocyclic carbene-metal complexes is reported. The protocol yields good to excellent results and minimizes solvent usage by only using environmentally benign solvents in the purification step.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Nedra Touj, Jerwin Jay Taping, Nikolay Tumanov, Johan Wouters, Lionel Delaude
Summary: The hydrolysis of imidazolinium chlorides occurs readily in a basic water/dichloromethane biphasic mixture at room temperature. Substrates with alkyl or aryl substituents on their nitrogen atoms led to high yields of gamma-aminoformamides. Bulky alkyl or aryl groups on the formamide moiety resulted in high stereoisomeric purity of the (E)-isomer. The presence of bulky aromatic substituents on the nitrogen atoms slowed down the hydrolysis of certain imidazolinium chlorides. The counteranion was found to have a critical influence on the reactivity of imidazolinium cations.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Long Zheng, Xueying Guo, Ying-Chao Li, Yichen Wu, Xiao-Song Xue, Peng Wang
Summary: In this study, the coupling of alkynes with Fischer-type copper carbene species bearing an alpha-siloxyl group is reported. The copper carbene species can be in situ generated from acylsilanes under photoirradiation and redox-neutral conditions. The side-arm modified bisoxazoline (SaBox) ligands play a crucial role in this coupling reaction, providing the corresponding alkynyl alcohol in high yields with remarkable heterocycle tolerance and broad substrate scope.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jingjing Zhang, Yingbo Shao, Hanliang Zheng, Xiao-Song Xue
Summary: This study describes the determination of the hydrogen bond acidity parameter A of the difluoromethylthio group (SCF2H) in the commonly used electrophilic difluoromethylthiolating reagent. Evidence of the RSCF2-H...O2 bifurcated hydrogen bond for stabilizing the SCF2H-transferring transition state is presented, which can lead to a reversal of the apparent electrophilic reactivity of difluoromethylthiolating and trifluoromethylthiolating reagents. The solvent effects on the RSCF2-H...O2 bifurcated hydrogen bonds are also discussed.
CHEMISTRY-AN ASIAN JOURNAL
(2023)
Article
Chemistry, Organic
Man -Ni Nie, Zhen Wang, Qian-Hang Niu, Jia-Xing Dai, Qi-Qi Wang, Jin-Song Peng, Pengju Ji
Summary: An equilibrium acidity scale for 16 Bro''nsted organic acids was established in a deep eutectic solvent. The scale showed a similar range to that in water. The solvent properties of the deep eutectic solvent were found to be different from other molecular solvents. The absorption capacity of carbon dioxide in anion-functionalized deep eutectic solvents was measured and found to be dependent on the basicity of the choline salt anion.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Shengjie Guo, Yueqian Sang, Chao Zheng, Xiao-Song Xue, Zhijun Tang, Wen Liu
Summary: The rare enzymatic precedent for the decarbonylation reaction has been discovered, which can effectively synthesize organic compounds. The on-line alpha-ketothioester decarbonylation reaction occurs during the first round of lipopeptide extension and modification in the NRPS-PKS assembly line of barbamide. The ketosynthase domain in BarE displays an unusual dual activity that results in a net one-carbon chain elongation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Ana Martin-Somer, K. N. Houk, Xiao-Song Xue, Cooper S. Jamieson, Yike Zou
Summary: An ambimodal transition state (TS) has been designed and explored using DFT computations and quasiclassical molecular dynamics, which leads to the formation of four different pericyclic reaction products without any intervening minima. Direct dynamics simulations starting from the ambimodal TS demonstrate the evolution of trajectories that result in the formation of the four cycloadducts. The product selectivity is influenced by the topography of the potential energy surface (PES), and a correlation is observed between the geometrical resemblance of the products to the ambimodal TS (measured by RMSD) and the ratio of products formed in the dynamics simulations.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Biochemistry & Molecular Biology
Cui Yu, Yueqian Sang, Yao Li, Xiaosong Xue
Summary: It has been widely accepted that nucleophiles prefer to attack the less sterically hindered carbon of epoxides under neutral and basic conditions. However, this rule does not apply to perfluorinated epoxides like HFPO, where nucleophiles attack the more hindered CF3 substituted beta-C instead of the fluorine substituted alpha-C. In this study, density functional theory calculations were used to explain this abnormal regioselectivity. The calculations reproduced the observed regioselectivities and attributed the preference for the sterically hindered beta-C of HFPO to the lower destabilizing distortion energy needed for the corresponding ring-opening transition state.
Article
Chemistry, Multidisciplinary
Xin Zeng, Yao Li, Qiao-Qiao Min, Xiao-Song Xue, Xingang Zhang
Summary: The use of metal catalysts in controlling the reactivity of carbenes is widely used in organic synthesis, but the transfer of difluorocarbenes remains a challenge. In this study, isolable copper(I) difluorocarbene complexes were developed and used as catalysts for difluorocarbene transfer reactions. This strategy allows for the modular synthesis of organofluorine compounds and provides access to a variety of difluoromethylene-containing products. Mechanistic studies reveal a nucleophilic addition mechanism involving electrophilic copper(I) difluorocarbenes.
Article
Chemistry, Organic
Liming Zhang, Haoran Xu, Weitao Liu, Chengwen Li, Yilin Zhao, Linhai Yan, Yangping Liu, Xianchao Cheng, Xiao-Song Xue, Guifang Han
Summary: A Cu(I)-catalyzed one-pot protocol utilizing benzyl group as a traceless redox-active hydrogen donor has been successfully developed for the hydro-difluoroalkylation of benzyl-protected acrylamides, leading to difluoropentanedioate compounds in moderate to excellent yields. Mechanistic investigations revealed that the reaction proceeds through the addition of a difluoroalkyl radical to acrylamide, followed by unexpected intramolecular 1,4-hydrogen atom transfer (HAT) and SET oxidation reaction. DFT calculations indicated that the chemoselectivity is controlled by destabilizing steric repulsion, resulting in the switch from 1,4-HAT to 5-exo spirocyclization. This work provides a crucial foundation for the application of 1,4-HAT reaction in theoretical and practical synthesis.
Article
Chemistry, Physical
Yuanyuan Ge, Yingbo Shao, Shuang Wu, Pan Liu, Junzhao Li, Hanzhang Qin, Yanxia Zhang, Xiao-song Xue, Yiyun Chen
Summary: In this study, the synthesis of distal amidoketones and nitrogen-functionalized ketones from alcohols and N-H nucleophiles using hypervalent iodine dimethyl benziodoxoles, BIm, is reported. BIm dually activates alcohols and various N-H nucleophiles by forming key BIm-O and BIm-N complexes, which were characterized by X-ray crystallography and computational investigation. Readily available N-H nucleophiles, including imides, sulfonamides, carbamates, triazoles, indazoles, and sulfoximines, engage in photoredox/copper catalysis to synthesize distal amidoketones and nitrogen-functionalized ketones with excellent regioselectivity and chemoselectivity. This reaction can be scaled up to grams, applied to late-stage complex molecule modification, and streamline synthetic routes.
Article
Multidisciplinary Sciences
Yongrui Luo, Yuli Li, Jian Wu, Xiao-Song Xue, John F. Hartwig, Qilong Shen
Summary: This study reports the mechanism of carbon-halogen bond cleavage in copper-catalyzed cross-coupling reactions. Stable copper(III) complexes were successfully synthesized through oxidative addition reactions, and different reaction pathways were explored. Additionally, it was found that ligand can accelerate the oxidative addition, which is consistent with observations in other copper-catalyzed coupling reactions.
Article
Chemistry, Physical
Rong-Gui Hu, Yueqian Sang, Fang-Fang Tan, Yuan-Li Sun, Xiao-Song Xue, Yang Li
Summary: Photoredox and vanadate cocatalyzed hydrolysis of aryl ethers enables the cleavage of C-O bonds at ambient temperature under mild reaction conditions. This method offers a preferred option for C-O bond cleavage and demonstrates potential application to lignin degradation.
Article
Chemistry, Physical
Yuanyuan Ge, Yingbo Shao, Shuang Wu, Pan Liu, Junzhao Li, Hanzhang Qin, Yanxia Zhang, Xiao-song Xue, Yiyun Chen
Summary: In this study, a method for the synthesis of distal amidoketones and nitrogen-functionalized ketones from alcohols and N-H nucleophiles using hypervalent iodine dimethyl benziodoxoles, BIm, is reported. The BIm compound activates both alcohols and various N-H nucleophiles, forming key BIm-O and BIm-N complexes. Photoredox/copper catalysis with readily available N-H nucleophiles such as imides, sulfonamides, carbamates, triazoles, indazoles, and sulfoximines enables the synthesis of distal amidoketones and nitrogen-functionalized ketones with high regioselectivity and chemoselectivity. This reaction can be scaled up to grams, applied to late-stage complex molecule modification, and simplifies synthetic routes.
Article
Chemistry, Multidisciplinary
Tao-Bin He, Bing-Chao Yan, Yuan-Fei Zhou, Yue-Qian Sang, Xiao-Nian Li, Han-Dong Sun, Chu Wang, Xiao-Song Xue, Pema-Tenzin Puno
Summary: This study reported an unprecedented class of cadinane sesquiterpene [4+2] dimers, which were synthesized using a protection-free approach, and revealed the origin of selectivity in the key [4+2] cycloaddition and the mechanism of inhibition of reaction pathway bifurcation. Chemical proteomics results showed that these compounds had multiple targets. This work provides experimental evidence and a powerful strategy for the discovery of novel compounds and exploration of the biological properties of natural products.
Article
Chemistry, Multidisciplinary
Zhenghong Zhou, Jimin Yang, Bo Yang, Yang Han, Lijuan Zhu, Xiao-Song Xue, Feng Zhu
Summary: This study presents a pioneering example of nickel-catalysed enantioconvergent Stille cross-coupling reactions. The reactions result in the formation of C-C bonds in good to high yields with excellent stereoselectivity, providing a practical and cost-effective method for synthesis. The innovative use of synergistic photoredox/nickel catalysis enables a novel single-electron transmetalation process, opening up new research possibilities in the field of Stille reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Ying Zhang, Jimin Yang, Yu-Long Ruan, Ling Liao, Chuang Ma, Xiao-Song Xue, Jin-Sheng Yu
Summary: This study developed an unprecedented nickel-catalyzed enantioselective hydromonofluoromethylation reaction, enabling the synthesis of valuable monofluoromethyl-tethered chiral allenes that were previously inaccessible. The method exhibits broad substrate scope, good functionality tolerance, mild reaction conditions, and the ability to construct other valuable fluorinated compounds.
