Article
Chemistry, Applied
Yang Zhou, Kevin J. Edgar
Summary: The site-specific conjugation of polysaccharides with proteins is challenging, but controlling the reaction between polysaccharides and amino acid derivatives can create useful bioactive natural polymer constructs. By using regioselective bromination, this study successfully synthesized polysaccharide-amino acid ester adducts, providing guidance for designing new pathways to polysaccharide-protein copolymers.
CARBOHYDRATE POLYMERS
(2022)
Article
Chemistry, Multidisciplinary
Sebastian Heindl, Margaux Riomet, Jan Matyasovsky, Miran Lemmerer, Nicolas Malzer, Nuno Maulide
Summary: A chemoselective and robust protocol for the gamma-oxidation of beta,gamma-unsaturated amides has been developed, showcasing the synthetic utility of the products obtained through radical cyclisation reactions and oxidation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
Nabin Sarkar, Rajata Kumar Sahoo, Sharanappa Nembenna
Summary: In this study, a molecular aluminium dihydride complex was used as a catalyst for reducing a wide range of aryl and alkyl esters, showing good tolerance towards other functional groups. The catalytic application of aluminium dihydride in the C-O bond cleavage of alkyl and aryl epoxides was also investigated, resulting in branched Markovnikov ring-opening products.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Biochemistry & Molecular Biology
Xiao-Lin Wang, Ji-Teng Chen, Sheng-Cai Zheng, Xiao-Ming Zhao
Summary: The utilization of 6,6-dimethyl-3-((trimethylsilyl)oxy)cyclohex-2-en-1-one, derived from an unsymmetrical 4,4-dimethylcyclohexane-1,3-dione, in iridium-catalyzed allylic enolization is achieved under mild conditions. The presence of a quaternary carbon and adjustment of reaction conditions enable high selectivities in terms of chemoselectivity, regioselectivity, and enantioselectivity. This method provides substituted 2-(but-3-en-2-yl)-3-hydroxy-6,6-dimethylcyclohex-2-en-1-ones in good to high yields with excellent chemo-, regio-, and enantioselectivities. Additionally, the formation of chiral carbon-fluorine bonds is induced by an adjacent chiral carbon center.
Article
Chemistry, Applied
Yeong-Jiunn Jang, Guan-Yu Chen, Yun-Lian Jhan, Pei-Ting Lo, Wei-Yu Hsu, Ke Wang, Ya-Ting Hsu, Chia-Lin Lee, Yu-Liang Yang, Yang-Chang Wu
Summary: A one-pot synthesis of substituted isocoumarin, flavone, and isoquinolinedione derivatives has been developed using a switchable C-arylation/lactonization or SNAr reaction. This base-mediated protocol proceeds under transition-metal-free conditions and selectively affords various heteroarenes in good yields. The synthetic utility of this method is demonstrated in the synthesis of potential anti-HIV and anti-coronavirus derivatives and COX-2 inhibitors. Detailed experimental and computational studies provide a comprehensive understanding of the reaction mechanism.
ADVANCED SYNTHESIS & CATALYSIS
(2023)
Article
Chemistry, Physical
Bing Zhang, Xueying Guo, Lei Tao, Ruolin Li, Zhenyang Lin, Wanxiang Zhao
Summary: The deoxygenative reduction of 1,3-diketones using a rhodium-catalyzed method exhibits high regioselectivity toward aliphatic carbonyl reduction, good functional group tolerance, and potential in the late-stage modification and synthesis of natural products and pharmaceutical skeletons. Preliminary mechanistic studies suggest a lower energy barrier for aliphatic C = O insertion, explaining the high regioselectivity observed in this reduction.
Article
Chemistry, Multidisciplinary
Yuse Kuriyama, Yusuke Sasano, Yoshihiko Hoshino, Shun-ichiro Uesugi, Aoto Yamaichi, Yoshiharu Iwabuchi
Summary: Highly regioselective intramolecular aminolysis of 3,4-epoxy amines has been achieved by chemoselective activation of epoxides in the presence of unprotected aliphatic amines in the same molecules using a La(OTf)(3) catalyst, resulting in excellent regioselectivity for anti-Baldwin 5-endo-tet cyclization and stereospecific formation of 3-hydroxy-2-alkylpyrrolidines in high yields. DFT calculations suggested that regioselectivity is attributed to distortion energies of epoxy amine substrates. This reaction was used in the enantioselective synthesis of an antispasmodic agent prifinium bromide.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Xuelun Duan, Nan Zheng, Ming Li, Xinhao Sun, Zhuye Lin, Pan Qiu, Wangze Song
Summary: Remote ether groups can be utilized as directing groups to achieve exclusive 1,5-regioselectivities and excellent chemoselectivities in the synthesis of fully substituted 5-ether-1,2,3-triazoles. Coordination of ether group with iridium catalyst enables control of regioselectivity through weak coordination effect. The chemoselective cycloaddition reaction occurs at the propargyl ether moiety of diyne, yielding unique fully substituted 4-alkynyl-triazole.
CHINESE CHEMICAL LETTERS
(2021)
Review
Chemistry, Multidisciplinary
Yang Ke, Wei Li, Wenfeng Liu, Wangqing Kong
Summary: Scaffold diversity is crucial for the success of compound libraries in biological screening. This review focuses on recent efforts in Ni-catalyzed divergent and selective synthesis, which generate structurally diverse molecular scaffolds using the same substrate and varying the ligand backbone under almost identical reaction conditions. The progress achieved encourages the design and development of new selective catalytic systems and reveals new modes of catalytic transformation for broader synthetic applications.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Organic
Juan Ye, Yang Wang
Summary: A comprehensive study on the mechanisms and origins of the chemoselectivity and regioselectivity of phosphine-catalyzed Rauhut-Currier reaction is performed by DFT. The computational results reveal that the cross R-C reaction is energetically favorable, with head-to-tail product being generated preferentially. The C-C bond formation process is identified as the determining step for regioselectivity and chemoselectivity.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Applied
Nian Zheng, Wei-Yu Shi, Ya-Nan Ding, Xue-Yuan Liu, Yong-Min Liang
Summary: Controllable chemoselectivity and regioselectivity synthesis of 3-sulfinylated, 3-sulfenylated and 2-sulfonylated indoles via direct C-H functionalization are achieved under metal-free conditions. The synthesis of 3-arylsulfinylindoles in high yields from a sulfone substrate in water without additives is particularly noteworthy. The use of p-Toluenesulfonyl cyanide (TsCN) as a new sulfur reagent through the cleavage of S-C and S=O bonds is also demonstrated.
ADVANCED SYNTHESIS & CATALYSIS
(2022)
Article
Chemistry, Multidisciplinary
Harjeet S. Soor, Diego B. Diaz, Katherine I. Burton, Andrei K. Yudin
Summary: The ongoing search for underdeveloped functional group combinations has led to the discovery of alpha-fluorinated aminoalkylboronic acids, a new class of molecules featuring the B-CF linkage. These compounds can be generated through electrophilic fluorination and show stability and unique structural properties.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Yulia O. Edilova, Ekaterina A. Osipova, Pavel A. Slepukhin, Victor I. Saloutin, Denis N. Bazhin
Summary: This paper presents a convenient method for the synthesis of substituted pyrazoles and pyridazinones based on 1,2,4-triketones. The chemo- and regiocontrol in condensations of different substituted 1,2,4-triketone analogs with hydrazines were studied. It was found that the direction of nucleophilic attack can be switched depending on the substituent nature in triketone and the reaction conditions. The acid and temperature effects on the selectivity of condensations were also revealed. The regiochemistry of heterocyclic core formation was confirmed by NMR and XRD studies. The facile construction of heterocyclic motifs bearing acetyl and (or) carbethoxy groups suggests them as promising mono- or bifunctional building blocks for subsequent transformations.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Kathleen M. Morrison, Charles S. Yeung, Mark Stradiotto
Summary: A systematic evaluation of competitive bisphosphine/Ni-catalyzed C-N versus C-O cross-couplings involving model compounds enabled the development of selective O- and N-arylation of amino alcohols with (hetero)aryl chloride electrophiles, without the need for protection group chemistry. The use of the CyPAd-DalPhos pre-catalyst C2 allowed for challenging O-arylation in amino alcohols with branched alkylamine groups, while selective N-arylation was observed in substrates with less hindered linear alkylamine and aniline groups. The reaction scope in (hetero)aryl chloride was broad, and the transformations could be conducted using benchtop handling of materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Christophe M. Saudan, Aurelien Berrocosa, Julie Quintaine, Stephanie Spoehrle, Laurent Maggi, Herve Mosimann, Lionel Saudan
Summary: This paper reports a method for the regio- and chemoselective hydrogenation of conjugated dienals using a large bite-angle diphosphine and a neutral rhodium complex catalyst in the presence of a weak base. This method offers high selectivity, mild reaction conditions, and a neutral alternative to the commonly employed Claisen rearrangement for the synthesis of γ,δ-unsaturated aldehydes.
