Article
Chemistry, Applied
Qingyu Yin, Zhiming Li, Fan Wu, Mingtong Ji, Chao Fu, Xiaoyu Wu
Summary: A diastereoselective and enantioselective conjugate addition of alpha-substituted acyl imidazole to nitroalkene catalyzed by nickel bisoxazoline complex and B(C6F5)(3) has been developed. The reaction showed broad substrate tolerance and high yields and enantioselectivity. The coordination catalyst and co-catalyst played a crucial role in the success of the reaction.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Organic
Nishikant Satam, Pallabita Basu, Soumyaranjan Pati, Irishi N. N. Namboothiri
Summary: A protocol for the stereoselective synthesis of alkylidenephthalides and indanediones has been developed, with mechanistic studies revealing the key role of phenolic groups in the observed reactivities. The alkylidenephthalides were further converted to triarylfurans in good yields, highlighting their potential as 1,4-dicarbonyl surrogates in Paal-Knorr furan synthesis.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Xu Ma, Yongliang Zhang, Xijun Zhu, Yongliang Wei, Liming Zhang
Summary: This work introduces a novel catalytic S(N)2 glycosylation method using an amide-functionalized 1-naphthoate platform as a latent glycosyl leaving group. The amide group facilitates the S(N)2 process by directing the attack of the glycosyl acceptor via H-bonding interaction, resulting in stereoinversion at the anomeric center. Additionally, the amide group enables a safeguarding mechanism by trapping oxocarbenium intermediates, minimizing stereorandom S(N)1 processes. This strategy allows for high-yielding synthesis of a wide range of glycosides with stereoinversion, including challenging 1,2-cis-linkage-rich oligosaccharides.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Organic
Yimin Hu, Wangyu Shi, Zhengyang Yan, Jianning Liao, Min Liu, Jiaqing Xu, Wei Wang, Yongjun Wu, Cheng Zhang, Hongchao Guo
Summary: An efficient method using K2CO3 catalysis has been developed for the 1,4-addition/intramolecular cyclization/aromatization reaction of aurone-derived 1-azadienes with trisubstituted allenoates, resulting in a series of benzofuro[3,2-b]pyridines in moderate to excellent yields. The reaction proceeds efficiently under an air atmosphere without the need for transition metal catalysts, providing a concise approach to benzofuro[3,2-b]pyridines.
Article
Chemistry, Multidisciplinary
Lin-Jun Qi, Cui-Ting Li, Zheng-Qi Huang, Jia-Tian Jiang, Xin-Qi Zhu, Xin Lu, Long-Wu Ye
Summary: The study presents a novel copper-catalyzed asymmetric formal annulation reaction, which can synthesize a range of chiral oxygen-heterocycles via carbonyl ylides with excellent enantioselectivity and yields.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Chada Raji Reddy, Ankita Kumari, Suraj Aswale, Amol D. Patil, Y. Lakshmi Prapurna
Summary: The reaction of alkynyl p-quinone methide (pQM) with keto-methylenes through a base-mediated tandem 1,6-addition/annulation sequence, [2 + 3] annulation, affords furans for the first time. Various functionalized furans, including fused derivatives, can be obtained in good to excellent yields under mild reaction conditions. The effectiveness of alkynyl pQMs is demonstrated by their ability to access isoxazoles, pyrazoles via [3 + 2] annulation, and pyridines through [3 + 3] annulation in the presence of different bis-nucleophiles.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Greta Vastakaite, Claudio E. Grunenfelder, Helma Wennemers
Summary: This study presents a tripeptide catalyst for the efficient and stereoselective synthesis of chiral succinimides via conjugate addition reactions between aldehydes and C-substituted maleimides. The catalyst exhibits high chemoselectivity and allows direct derivatization of the succinimides to access other chiral compounds.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Organic
Chun Yang, Xinying Zhang, Xuesen Fan
Summary: Presented herein is a novel synthesis method for homophthalimide spironaphthalenones through the cascade reaction of enaminones with diazo homophthalimides. The mechanism involves Rh(iii)-catalyzed C(sp(2))-H metalation of enaminone and coordination with diazo homophthalimide, followed by migratory insertion, spiroannulation, beta-elimination, and protonation. This transformation defines a new and distinct reaction pattern of enaminone, acting as an effective C5 synthon for [5 + 1] spiroannulation. Overall, this developed protocol offers easily accessible substrates, valuable products, mild reaction conditions, concise synthetic procedure, high efficiency, and compatibility with diverse functional groups.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Physical
Subramanian Thiyagarajan, Raman Vijaya Sankar, Puthannur K. Anjalikrishna, Cherumuttathu H. Suresh, Chidambaram Gunanathan
Summary: This article describes a simple method for the coupling of nitriles with allylic alcohols catalyzed by a ruthenium pincer complex. Mechanistic studies were conducted to investigate the catalytic cycle. The method demonstrated tolerability towards reactive functional groups such as carbamate, sulfonate, olefin, cyano, and trifluoromethyl-substituted benzyl nitriles. Additionally, the synthesis of anipamil drug and the utility of delta-hydroxynitrile products in the synthesis and functionalization of biologically active molecules were demonstrated.
Article
Chemistry, Applied
Feroz Ahmad, Pavit K. Ranga, Shaheen Fatma, Arun Kumar, Ramasamy Vijaya Anand
Summary: This article describes an effective and economical method for synthesizing various important functionalized indolizine derivatives. This transformation is achieved through a Cu(II)-catalyzed [3+2] annulation of 2-pyridinyl substituted p-quinone methides with enaminones. The method has good functional group tolerance and is effective for most enaminones and p-QMs, resulting in moderate to good yields of indolizines.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Multidisciplinary
Hu Tian, Hong-Ming Zhang, Liang Yin
Summary: In this article, a copper(I)-catalyzed asymmetric conjugate addition/protonation with selenols and alpha-substituted alpha,beta-unsaturated thioamides is described, which produces a series of chiral selenides with high to excellent enantioselectivity. The reaction shows a broad substrate scope for both selenols and alpha-substituted alpha,beta-unsaturated thioamides. The catalytic system is also successfully used for asymmetric selenation of beta-substituted alpha,beta-unsaturated thioamides. A [Cu-(R,R-P)-TANIAPHOS]-SePh species is identified by Se-77 NMR spectra, with a chemical shift at delta 462 ppm. Furthermore, a {[Cu-(R)-TOL-BINAP]-SePh}(2) species is characterized by X-ray analysis, confirming the formation of Cu-Se bond in the reaction. Finally, the straightforward transformations of the thioamide group to amine and thioester are demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Rohit Kumar, Vipin Kumar Jain, Nidhi Jain
Summary: A mild and efficient ruthenium-catalyzed hydroxy-arylation reaction of the terminal double bond of N-substituted 3-methyleneisoindolin-1-ones is described in this study. The reaction takes place in the presence of aryl diazonium salt as arylating reagent and water as hydroxyl source under visible light at ambient temperature. This strategy enables the construction of 3-benzyl-3-hydroxyisoindolin-1-one heterocyclic scaffolds through vicinal difunctionalization of the alkene, yielding moderate to good yields. Both C-C and C-O bonds are formed in one pot without the need for external additives or oxidants, through the in situ generation of a carbocation intermediate under green light.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Yuhao Mo, Qiyou Chen, Jinzhao Li, Dong Ye, Yuqiao Zhou, Shunxi Dong, Xiaohua Liu, Xiaoming Feng
Summary: A highly enantioselective conjugate cyanation of cyclic a,fi-unsaturated ketones was successfully achieved using chiral Lewis acids and achiral organic bases as dual catalysts. Various chromones and fi-substituted cyclohexenones were efficiently converted into the desired fi-cyano ketone derivatives with good yields and high enantioselectivities under mild reaction conditions. The combination of metal salts Ce(OTf)3 and Ba(OTf)2 with chiral N,N'-dioxides proved to be effective in facilitating the reaction, showing a strong correlation between the reaction outcome and the Lewis acidity influenced by the metal ion radii. The practical utility of this methodology was demonstrated through the facile synthesis of the bioactive compounds repinotan and sarizotan.
Review
Chemistry, Multidisciplinary
Xingyu Shen, Danny Q. Thach, Chi P. Ting, Thomas J. Maimone
Summary: Annulation reactions, from Robinson annulation to Diels-Alder cycloaddition, have driven the advancement of natural product synthesis in the past century. The ability to form cyclic molecules directly from simpler fragments has transformed various aspects of chemical sciences. By combining annulation with oxidative rearrangement, a wide range of natural products containing bicyclo[3.3.1]nonane cores have been successfully synthesized, demonstrating the broad applicability of this strategy.
ACCOUNTS OF CHEMICAL RESEARCH
(2021)
Article
Chemistry, Organic
Sudip Shit, Surjya Kumar Bora, Archana Kumari Sahu, Anil K. Saikia
Summary: This study demonstrates the synthesis of spiro[furan-2,1'-isoindolin]-3'-ones from 2-(4-hydroxybut-1-yn-1-yl)benzonitriles and aryl aldehydes. The reaction involves the formation of dihydrofuranylideneisoindolinone through intramolecular Prins and Ritter reactions, followed by ring opening and cyclization to produce the spiro-cyclic compounds.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Haoyu Li, Xinxin Tang, Jia Hao Pang, Xiangyang Wu, Edwin K. L. Yeow, Jie Wu, Shunsuke Chiba
Summary: This study reveals the use of polysulfide anions as visible light photoredox catalysts for aryl cross-coupling reactions. By photoexcitation of tetrasulfide dianions, single-electron reduction of aryl halides is achieved, leading to the participation of aryl radicals in cross-coupling, borylation, and hydrogenation reactions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Organic
Yuliang Liu, Haoyu Li, Shunsuke Chiba
Summary: A protocol for photoinduced cross-coupling of aryl iodides and alkenes has been developed, utilizing a radical cascade mechanism. This method enables selective coupling of iodides over other halogen leaving groups and is compatible with various functional groups on both arene and alkene motifs.
Article
Chemistry, Multidisciplinary
Jia Hao Pang, Bin Wang, Kohei Watanabe, Ryo Takita, Shunsuke Chiba
Summary: A method for the efficient synthesis of 1,3-diarylpropylamines through hydroalkylation of benzylamines and styrenes catalyzed by potassium hydride under solvothermal conditions has been developed.
HELVETICA CHIMICA ACTA
(2021)
Article
Chemistry, Physical
Yi Zhen Tan, Xiangyang Wu, Thanh Nhut Do, Hoang Long Nguyen, Howe-Siang Tan, Shunsuke Chiba, Edwin K. L. Yeow
Summary: In this study, the existence of an overlooked electron transfer process from N-MP to photoexcited Rh6G(+) was demonstrated using steady-state and time-resolved spectroscopy techniques. This process led to the formation of short-lived radicals that underwent rapid recombination, inhibiting the reduction of Ar-X to aryl radicals and thereby affecting the efficiency of the cross-coupling reaction.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Organic
Yihang Li, Jia Sheng Ng, Bin Wang, Shunsuke Chiba
Summary: A protocol for synthesizing alpha-alkynylnitrones from 1,3-enynes has been developed using MgH2 triggered hydromagnesiation. The resulting alpha-alkynylnitrones can serve as versatile precursors for constructing various nitrogen-containing compounds.
Article
Chemistry, Organic
Jiahua Chen, Jun Wei Lim, Shunsuke Chiba
Summary: An facile method for the conversion of 2-piperidones and 2-pyrrolidones into 2-cyano-3-iodo piperidines or pyrrolidines has been achieved through a sequence of controlled hydride reduction, silylation, iodination, and cyanation, resulting in high diastereoselectivity and good yields.
Article
Chemistry, Multidisciplinary
Yihang Li, Jiahua Chen, Jaslyn Jing Wen Ng, Shunsuke Chiba
Summary: A protocol was developed to generate allylmagnesium reagents from 2-aryl-1,3-dienes using in situ generated magnesium hydride (MgH2) through solvothermal treatment of sodium hydride (NaH) and magnesium iodide (MgI2) in tetrahydrofuran (THF). Downstream functionalization of the resulting allylmagnesium reagents with carbonyl compounds or alkyl (pseudo)halides led to branched products with an allylic quaternary carbon center, while reaction with chlorosilanes resulted in regio and stereoselective formation of linear allylsilanes. Further derivatizations of the homoallylic alcohols and allylsilanes were also demonstrated.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Eugene Yew Kun Tan, Amirah S. Mat Lani, Wayne Sow, Yuliang Liu, Haoyu Li, Shunsuke Chiba
Summary: The facile construction of C(sp(3))-rich carbo- and heterocyclic compounds is an important synthetic strategy for contemporary drug discovery programs. In the presence of potassium formate and methanol under visible light irradiation, polysulfide anions can catalyze the dearomatization process of substituted naphthalenes, indoles, and other related heteroaromatic compounds. This method demonstrates broad functional group tolerance, operational simplicity, scalability, and cost-effectiveness, making it a practical and sustainable synthetic tool for arene dearomatization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Itziar Guerrero, Eugene Yew Kun Tan, Yuliang Liu, Lee J. Edwards, Shunsuke Chiba
Summary: A photochemical protocol has been developed for the alkylation of diazines (pyrimidines, pyrazines, and pyridazines) with N-(acyloxy)phthalimides. The process is facilitated by the presence of triethylamine under irradiation with 427-390 nm light, enabling rapid cross-coupling reactions to construct a wide range of alkylated diazines.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Eugene Yew Kun Tan, Amirah S. Mat Lani, Wayne Sow, Yuliang Liu, Haoyu Li, Shunsuke Chiba
Summary: The study demonstrates a method using polysulfide anions to catalyze the dearomatization process under visible light irradiation. The developed protocol exhibits broad functional group tolerance, operational simplicity, scalability, and cost-effectiveness, making it a practical synthetic tool.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Yi Zhen Tan, Xiangyang Wu, Yunpeng Lu, Shunsuke Chiba, Edwin K. L. Yeow
Summary: In this study, the researchers found that the heteroleptic Ir(iii) complex 1, combined with N-(tert-butoxycarbonyl)-proline and cesium carbonate, can facilitate the hydrodehalogenation of reductively inert aryl halides under blue light irradiation. The in situ modified Ir-int structure leads to a bathochromic shift of excited triplet state absorption and phosphorescence bands. Free Ir-int ions are responsible for the hydrodehalogenation reaction of aryl halides.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Haoyu Li, Shunsuke Chiba
Summary: A photocatalytic method using polysulfide anions as catalysts enables the synthesis of alpha-tertiary amines through alpha-C-H functionalization of a-secondary benzylamines with cyanoarenes or aryl ketones. The key factors include the highly negative oxidation potential of polysulfide dianions and the catenated structure of polysulfide anion radicals, facilitating the construction of sterically congested alpha-tertiary amine scaffolds.
Article
Chemistry, Physical
Yuliang Liu, Haoyu Li, Eugene Yew Kun Tan, Erik Budi Santiko, Youhei Chitose, Manabu Abe, Shunsuke Chiba
Summary: In this study, we demonstrated the design and synthesis of PIqs with electron-withdrawing groups, which exhibit wider redox windows and higher triplet-state energies under visible light irradiation. By modifying the positions and structures of these electron-withdrawing groups, the photophysical and electrochemical properties of PIqs can be tailored, enabling a range of molecular transformations driven by visible light.
Article
Chemistry, Multidisciplinary
Yoshiya Sekiguchi, Jia Hao Pang, Jia Sheng Ng, Jiahua Chen, Kohei Watanabe, Ryo Takita, Shunsuke Chiba
Summary: Solvothermal treatment of 1-naphthylmethylamine with KH or n-BuLi / t-BuOK in THF results in two consecutive beta-hydride eliminations, yielding 1-naphthonitrile and KH. The freshly generated KH can undergo dearomative hydride addition to the resulting 1-naphthonitrile at the C4 position, forming alpha-cyano benzylic carbanion, which can be further functionalized to obtain 1,4-dihydronaphthalene-1-carbonitriles with a quaternary carbon center.
Article
Chemistry, Multidisciplinary
Haoyu Li, Yuliang Liu, Shunsuke Chiba
Summary: This perspective summarizes recent advances in using sulfur anions to promote molecular transformations under visible light irradiation, with focus on the role of sulfur anions in different reaction modes.
