Article
Chemistry, Organic
Kyeong Seop Kim, Dae Young Kim
Summary: This study describes an electrochemical C-H oxidation/conjugate addition/cyclization reaction that enables the reaction between 2-alkyl phenols and malononitrile under mild reaction conditions, resulting in the synthesis of various 2-amino-4H-chromene derivatives in high yields. This method offers an environmentally friendly approach by eliminating the use of stoichiometric amounts of external redox reagents.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Jihoon Jang, Dae Young Kim
Summary: A new visible light-mediated photocatalytic approach has been developed for the multicomponent synthesis of trifluoromethylated 4H-chromenes from 2-vinyl phenols via trifluoromethylation, oxidation, and cycloaddition reactions, involving the in situ generation of o-quinone methides followed by sequential cyclization.
ASIAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Kyeong Seop Kim, Dae Young Kim
Summary: In this study, chiral 2-amino-4H-chromene derivatives were synthesized from 2-alkyl-substituted phenol derivatives via a one-pot cascade reaction using a binaphthyl-modified organocatalyst with low catalyst loading (1.25 mol%). The reaction showed moderate to high yields and excellent enantioselectivities.
SYNTHETIC COMMUNICATIONS
(2022)
Article
Chemistry, Organic
Sabrina Giofre, Manfred Keller, Leonardo Lo Presti, Egle M. Beccalli, Letizia Molteni
Summary: The study demonstrates that the Pd(II)-catalyzed reaction of N-allyl-2-aminophenols can lead to different pathways and products under different conditions, with the oxidant playing a key role in the reaction.
Article
Chemistry, Organic
Diksha Rajput, Gowsia Jan, Muthu Karuppasamy, Nattamai Bhuvanesh, Subbiah Nagarajan, C. Uma Maheswari, J. Carlos Menendez, Vellaisamy Sridharan
Summary: An efficient cascade annulation reaction using secondary amine catalyst was developed for the synthesis of functionalized 2H-chromenes and 1,2-dihydroquinolines with a p-quinone methide scaffold. The microwave-assisted strategy achieved high yields and completion of reactions in just 15 min. The synthesized products were further transformed into valuable compounds via a palladium-catalyzed double C-H bond activation process and epoxidation.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Guangming Nan, Jingbo Zhan, Chunming Yuan, Lirong Wen, Ming Li
Summary: This novel method involves the synthesis of highly substituted 4H-chromene derivatives through NEt3-promoted annulation of beta-ketothioamides and ortho-quinone methides. The method exhibits good functional group tolerance, simple operation, and scalability.
CHINESE JOURNAL OF ORGANIC CHEMISTRY
(2021)
Review
Chemistry, Organic
Shi-Lu Zheng, Long Chen
Summary: 2H-chromenes, as an important type of oxygen heterocycles, are widely found in natural products, pharmaceutical agents, and biologically relevant molecules. The synthesis of such compounds mainly involves benzopyran ring formation and late-stage functionalization of the parent 2H-chromenes.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)
Article
Chemistry, Organic
Zhong Wen, Kai-Cheng Yang, Shi-Lu Zheng, Yu-Shan Zhang, Sheng-Jun Wang, Hai-Liang Ni, Long Chen
Summary: A Hg(OTf)(2)-catalyzed tandem reaction has been developed for the preparation of 4-phosphorylated 4H-chromenes. This protocol allows the construction of C-P and C-O bonds in a one-pot operation, providing a new and efficient approach for the synthesis of 4H-chromenes.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Sajjad Ahmed, Mohammad Yaqoob Bhat, Feroze Hussain, Qazi Naveed Ahmed
Summary: In this study, the activation of diphenyl phosphite by BF3/BF4(-) resulted in the formation of thionium ions from aldehydes and thiophenols. These reactive species then reacted with in situ generated phenol, leading to the synthesis of diarylmethyl thioethers. It was found that the addition of external phenol in the reaction yielded unsymmetrical gem-diarylmethyl thioethers in good yields.
Article
Chemistry, Organic
Pushpendra Mani Shukla, Aniruddh Pratap, Biswajit Maji
Summary: A diastereoselective N-heterocyclic carbene-catalysed reaction has been developed for accessing a new type of C-4-functionalized 2-amino-3-cyano-4H-chromene. Various enals and iminochromenes afforded the desired homoenolate addition product 2-amino-4H-chromenes in good yields and with moderate to good diastereoselectivities.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2022)
Article
Chemistry, Organic
Ganesh Shivayogappa Sorabad, Ding-Yah Yang
Summary: A facile and regioselective Lewis acid-catalyzed cascade annulation of o-hydroxyphenyl propargyl amines with 4-hydroxycoumarin to afford furano[3,2-c]coumarin and pyrano[3,2-c]coumarin derivatives is reported. The reaction proceeds through the conjugate addition of 4-hydroxycoumarin to the in situ-generated alkynyl o-quinone methide followed by intramolecular 5-exo-dig and 6-endo-dig annulation to form furano[3,2-c]coumarins and pyrano[3,2-c]coumarins, respectively. The prepared o-hydroxyl substituted pyrano[3,2-c]coumarins can be easily transformed into the corresponding coumarin-derived dioxabicycles by acid-mediated cyclization.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Kai Li, Shengli Huang, Tianyu Liu, Shiqi Jia, Hailong Yan
Summary: We demonstrated an organocatalytic asymmetric dearomatizing hetero-Diels-Alder reaction of benzene derivatives, which allows the synthesis of diverse stereochemically complex compounds and oxahelicenes. The high complexity and three-dimensionality of the products are crucial for their potential applications in materials science and drug discovery.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Organic
Qinfang Yan, Yi Jiang, Xianheng Song, Guoqing Lu, Qianzhong Zhang, Zhibo Du, Albert S. C. Chan, Yong Zou
Summary: A facile and practical approach for the synthesis of natural coumestans and derivatives starting from 2',4'-dihydroxyl-3-arylcoumarins has been developed. The process involves a sequential intramolecular dehydrogenation/oxa-Michael reaction efficiently promoted by 1,8-diazabicyclo[5.4.0]undec-7-ene at 40 degrees C under metal- and ligand-free conditions with good functional group compatibility.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Maria Tereza M. Martins, Flaviana Rodrigues F. Dias, Raphael Silva M. de Moraes, Marcos Felipe da Silva, Kaio R. Lucio, Karin D'Oliveira Goes, Patrick A. do Nascimento, Andre S. S. da Silva, Vitor F. Ferreira, Anna C. Cunha
Summary: This article provides an overview of multicomponent reactions (MCRs) that involve ortho-quinone methide intermediates (o-QM) and discusses their applications in organic synthesis and biological processes. QMs are generated through eliminative processes or photochemical reactions and can undergo various types of reactions.
Article
Chemistry, Organic
Alemayehu Gashaw Woldegiorgis, Haorui Gu, Xufeng Lin
Summary: The organocatalytic asymmetric reactions of C2-unsubstituted racemic naphthyl-indoles with orthoalkynylnaphthols were used to synthesize axially chiral styrenes connected to an axially chiral naphthyl-indole unit. By employing chiral phosphoric acid as the catalyst, these axially chiral styrenes were obtained in good yields (up to 96%) and excellent stereoselectivity (up to >99.9% ee, >20:1 dr, and >99:1 E/Z) under mild conditions. Furthermore, further synthetic transformations were achieved with high yields and excellent stereocontrol.
Article
Chemistry, Multidisciplinary
Xiaoqing Wang, Yuqing Bai, Xiaoyong Zhai, Bo Wu, Yonggui Zhou
Summary: An environmentally sustainable copper-catalyzed dehydrocoupling polymerization method was developed for efficient preparation of poly(silyl ether)s (PSEs) with high yields and molecular weight. The PSEs exhibit good thermal stability and low glass-transition temperature.
CHINESE CHEMICAL LETTERS
(2022)
Article
Polymer Science
Xiao-Qing Wang, Yu-Qing Bai, Kun Wang, Bo Wu, Yong-Gui Zhou
Summary: This paper presents a metal-free insertion polymerization method for constructing carbon-heteroatom bonds in the main chain. Sulfoxonium ylides are used as monomers to produce polythioethers and aromatic polyamines with high yield and molecular weight. The method features mild conditions, easy operation, and a wide range of substrate applicability.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Chemistry, Organic
Jie Lin, Zilong Huang, Juan Ma, Bao-Hua Xu, Yong-Gui Zhou, Zhengkun Yu
Summary: Efficient palladium-catalyzed reactions were utilized to synthesize diverse compounds, including trisubstituted 1,3-dienes and tetrasubstituted allenes. The chemo- and regioselectivities were controlled to obtain structurally diverse products.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Organic
Yunlong Li, Wenchao Jiang, Jie Lin, Juan Ma, Bao-Hua Xu, Yong-Gui Zhou, Zhengkun Yu
Summary: In this study, triple C-H bond activation of aryl enaminones was achieved to access naphtho[1,8-bc]pyrans through oxidative annulation. Depending on the steric and/or electronic environment around the aryl moiety of the enaminones or the electronic impact from the alkynes, 1-naphthols might be formed as the sole products. By using propargyl alcohols as masked terminal alkynes, functionalized but-2-ene-1,4-diones were obtained through rhodium(III)- or rhodium(I)-catalyzed internal alkenyl C-H bond activation. The resulting naphtho[1,8-bc]pyrans exhibited high fluorescence and could be further transformed by chlorination, bromination, and difluoromethylation, demonstrating the potential applicability of the synthetic protocol.
Article
Chemistry, Applied
Zilong Huang, Jie Lin, Juan Ma, Liandi Wang, Yong-Gui Zhou, Zhengkun Yu
Summary: Carbene insertion into C(sp(2))-H bonds of internal alkenes was achieved in air using HFIP as both the mediator and solvent, along with borane B(C6F5)(3) as the catalyst. The reaction showed high yields (47-84%) and broad substituent tolerance, providing an efficient route to synthesize 3-vinylated oxindole and indole derivatives.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Xiang Li, Gao-Wei Wang, Li-Xia Liu, Chang-Bin Yu, Yong-Gui Zhou
Summary: Here, the authors describe the first example of palladium-catalyzed asymmetric hydrogenolysis of easily accessible aryl triflates for the construction of axially chiral biaryl scaffolds. The resulting chiral biaryl compounds were used to prepare axially chiral monophosphine ligands, which were further employed in palladium-catalyzed asymmetric allylic alkylation with excellent enantioselectivities and high branched and linear ratios, highlighting the potential utility of this methodology.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Organic
Tong Niu, Li-Xia Liu, Bo Wu, Yong-Gui Zhou
Summary: A series of [2,2]paracyclophane-based tridentate PNO ligands with planar chirality were designed and synthesized. These easily prepared chiral tridentate PNO ligands were successfully applied to the iridium-catalyzed asymmetric hydrogenation of simple ketones, providing chiral alcohols with high efficiency and excellent enantioselectivities (up to 99% yield and >99% ee). Control experiments demonstrated the indispensability of both N-H and O-H in the ligands.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Zilong Huang, Jie Lin, Mingrui Li, Zhengkun Yu, Yong-Gui Zhou
Summary: A zinc(II)-catalyzed [2+2+1] annulation reaction of internal alkenes, diazooxindoles, and isocyanates was developed for the efficient synthesis of multisubstituted spirooxindoles. This multi-component transformation involves the in situ formation of a sulfur-containing spirocyclic intermediate, followed by a 1,3-dipolar addition reaction of the intermediate with the internal alkene, resulting in a formal [2+2+1] annulation in a one-pot manner. The synthetic protocol utilizes a low-toxicity main group metal catalyst, readily available reagents, and provides high yields of up to 96% for the synthesis of multisubstituted spirooxindole derivatives.
Review
Chemistry, Multidisciplinary
Xiao Xiao, Kaini Xu, Zhong-Hua Gao, Zhou-Hao Zhu, Changqing Ye, Baoguo Zhao, Sanzhong Luo, Song Ye, Yong-Gui Zhou, Senmiao Xu, Shou-Fei Zhu, Hongli Bao, Wei Sun, Xiaoming Wang, Kuiling Ding
Summary: Enzymes are essential for biological transformations and have attracted great attention for their structures and functions. Biomimetic chemistry has rapidly developed in response to the demand for bioactive molecules and efficient synthesis. Biomimetic asymmetric catalysis, inspired by enzymes, has been recognized as one of the most promising strategies for producing valuable chiral compounds. This review summarizes the evolution of biomimetic asymmetric catalysis in terms of biomimetic design, catalyst development, and catalytic transformations, providing insights into bridging the gap between bio-catalysis and chemical synthesis.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Organic
Zheng Liu, Sheng-Mei Lu, Bao-Qian Zhao, Hao-Dong Chen, Mu-Wang Chen, Yong-Gui Zhou
Summary: A method using zinc chloride was developed to purify compounds with pyridine structure from Mitsunobu reaction mixtures, and a sulfide anion was used to release bipyridines from Ullmann coupling reaction mixtures by competitively coordinating the copper ion. These improvements enabled the facile synthesis of the chiral 2,2'-bipyridine ligand (R-a,S,S)-C3-ACBP, achieving an overall yield of 48% at a 7 gram scale within 3-4 days without column chromatography.
SYNTHESIS-STUTTGART
(2023)
Article
Chemistry, Multidisciplinary
Li-Xia Liu, Yu-Qing Bai, Xiang Li, Chang-Bin Yu, Yong-Gui Zhou
Summary: Combining base-promoted retro-sulfa-Michael addition with palladium-catalyzed asymmetric allenylic alkylation, a streamlined synthesis of chiral thiochromanones containing two central chiralities (including a quaternary stereogenic center) and an axial chirality (allene unit) was successfully achieved, with yields up to 98%, dr of 49.0:1, and >99% ee.
Article
Chemistry, Organic
Wen-Jun Huang, Li-Xia Liu, Yong-Gui Zhou, Bo Wu, Guo-Fang Jiang
Summary: We report a Bronsted acid-catalyzed C6 functionalization of 2,3-disubstituted indoles with 2,2-diarylacetonitriles for efficient construction of cyano-substituted all-carbon quaternary centers with excellent yields. The synthetic utility was demonstrated by the conversion of the cyano-group which enables the divergent preparation of aldehydes, primary amines and amides. Control experiments suggested that this process involves C-H oxidation of 2,2-diarylacetonitriles to in situ generate d,d-disubstituted p-quinone methide intermediates. This protocol provides an efficient method for C6 functionalization of 2,3-disubstituted indoles to construct all-carbon quaternary centers.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2023)
Article
Chemistry, Organic
Yixuan Ding, Yonggui Zhou
CHINESE JOURNAL OF ORGANIC CHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Yuan He, Zilong Huang, Kaikai Wu, Juan Ma, Yong-Gui Zhou, Zhengkun Yu
Summary: C-H functionalization is an effective method for establishing carbon-carbon and carbon-heteroatom bonds, and has made significant progress. Transition-metal-catalyzed carbene insertion to C-H bonds is one of the hot research topics in this field, with various catalyst design strategies and synthetic methods. This review summarizes the research progress up to July 2021 and discusses future directions.
CHEMICAL SOCIETY REVIEWS
(2022)
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)