1
|
Schmidt TA, Hutskalova V, Sparr C. Atroposelective catalysis. Nat Rev Chem 2024; 8:497-517. [PMID: 38890539 DOI: 10.1038/s41570-024-00618-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2024] [Indexed: 06/20/2024]
Abstract
Atropisomeric compounds-stereoisomers that arise from the restricted rotation about a single bond-have attracted widespread attention in recent years due to their immense potential for applications in a variety of fields, including medicinal chemistry, catalysis and molecular nanoscience. This increased interest led to the invention of new molecular motors, the incorporation of atropisomers into drug discovery programmes and a wide range of novel atroposelective reactions, including those that simultaneously control multiple stereogenic axes. A diverse set of synthetic methodologies, which can be grouped into desymmetrizations, (dynamic) kinetic resolutions, cross-coupling reactions and de novo ring formations, is available for the catalyst-controlled stereoselective synthesis of various atropisomer classes. In this Review, we generalize the concepts for the catalyst-controlled stereoselective synthesis of atropisomers within these categories with an emphasis on recent advancements and underdeveloped atropisomeric scaffolds beyond stereogenic C(sp2)-C(sp2) axes. We also discuss more complex systems with multiple stereogenic axes or higher-order stereogenicity.
Collapse
Affiliation(s)
- Tanno A Schmidt
- Department of Chemistry, University of Basel, Basel, Switzerland
| | | | - Christof Sparr
- Department of Chemistry, University of Basel, Basel, Switzerland.
| |
Collapse
|
2
|
Ževart T, Pinter B, Lozinšek M, Urankar D, Jansen-van Vuuren RD, Košmrlj J. Towards structurally versatile mesoionic N-heterocyclic olefin ligands and their coordination to palladium, gold, and boron hydride. Dalton Trans 2024; 53:8915-8925. [PMID: 38590282 DOI: 10.1039/d4dt00195h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
We have developed an efficient and versatile approach for the synthesis of a family of 1,2,3-triazole-based mesoionic N-heterocyclic olefin (mNHO) ligands and investigated their coordination to palladium, gold, and boron hydride experimentally and computationally. We reacted mNHOs obtained through deprotonation of the corresponding methylated and ethylated 1,3,4-triaryl-1,2,3-triazolium salts with [Pd(allyl)Cl]2 to give the corresponding [Pd(η3-allyl)Cl(mNHO)] coordination complexes. 13C NMR data revealed the strong σ-donor character of the mNHO ligands, consistent with the calculated bond orders and atom-condensed charges. Furthermore, we also synthesized [AuCl(mNHO)] and a BH3-mNHO adduct by reacting the triazolium salts with AuCl(SMe2) and BH3·THF, respectively. The BH3-mNHO adduct was tested in the reduction of select aldehydes and ketones to alcohols.
Collapse
Affiliation(s)
- Tisa Ževart
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI 1000 Ljubljana, Slovenia.
| | - Balazs Pinter
- The University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, USA
| | - Matic Lozinšek
- Jožef Stefan Institute, Jamova cesta 39, SI 1000 Ljubljana, Slovenia
| | - Damijana Urankar
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI 1000 Ljubljana, Slovenia.
| | - Ross D Jansen-van Vuuren
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI 1000 Ljubljana, Slovenia.
| | - Janez Košmrlj
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI 1000 Ljubljana, Slovenia.
| |
Collapse
|
3
|
Wang Y, Xu T, Jin S, Wang JY, Yuan Q, Liu H, Tang Y, Zhang S, Yan W, Jiao Y, Li G. Design and Asymmetric Control of Orientational Chirality by Using the Combination of C(sp 2)-C(sp) Levers and Achiral N-Protecting Group. Chemistry 2024; 30:e202400005. [PMID: 38497560 DOI: 10.1002/chem.202400005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/17/2024] [Accepted: 03/18/2024] [Indexed: 03/19/2024]
Abstract
New chiral targets of orientational chirality have been designed and asymmetrically synthesized by taking advantage of N-sulfinyl imine-directed nucleophilic addition/oxidation, Suzuki-Miyaura, and Sonogashira cross-coupling reactions. Orientation of single isomers has been selectively controlled by using aryl/alkynyl levers [C(sp2)-C(sp) axis] and tBuSO2- protecting group on nitrogen as proven by X-ray diffraction analysis. The key structural characteristic of resulting orientational products is shown by remote through-space blocking manner. Seventeen examples of multi-step synthesis were obtained with modest to good chemical yields and complete orientational selectivity.
Collapse
Affiliation(s)
- Yu Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Ting Xu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Shengzhou Jin
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Jia-Yin Wang
- School of Pharmacy, Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu, 213164, China
| | - Qingkai Yuan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, 79409-1061, USA
| | - Hao Liu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, 79409-1061, USA
| | - Yao Tang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, 79409-1061, USA
| | - Sai Zhang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, 79409-1061, USA
- School of Pharmacy, Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu, 213164, China
| | - Wenxin Yan
- School of Chemistry and Chemical Engineering, Key Laboratory of Theoretical Organic Chemistry and Functional Molecular, Ministry of Education, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Yinchun Jiao
- School of Chemistry and Chemical Engineering, Key Laboratory of Theoretical Organic Chemistry and Functional Molecular, Ministry of Education, Hunan University of Science and Technology, Xiangtan, 411201, China
| | - Guigen Li
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, 79409-1061, USA
| |
Collapse
|
4
|
Xu T, Wang JY, Wang Y, Jin S, Tang Y, Zhang S, Yuan Q, Liu H, Yan W, Jiao Y, Yang XL, Li G. C(sp)-C(sp) Lever-Based Targets of Orientational Chirality: Design and Asymmetric Synthesis. Molecules 2024; 29:2274. [PMID: 38792134 PMCID: PMC11123770 DOI: 10.3390/molecules29102274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/06/2024] [Accepted: 05/07/2024] [Indexed: 05/26/2024] Open
Abstract
In this study, the design and asymmetric synthesis of a series of chiral targets of orientational chirality were conducted by taking advantage of N-sulfinylimine-assisted nucleophilic addition and modified Sonogashira catalytic coupling systems. Orientational isomers were controlled completely using alkynyl/alkynyl levers [C(sp)-C(sp) axis] with absolute configuration assignment determined by X-ray structural analysis. The key structural element of the resulting orientational chirality is uniquely characterized by remote through-space blocking. Forty examples of multi-step synthesis were performed, with modest to good yields and excellent orientational selectivity. Several chiral orientational amino targets are attached with scaffolds of natural and medicinal products, showing potential pharmaceutical and medical applications in the future.
Collapse
Affiliation(s)
- Ting Xu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China; (T.X.); (Y.W.); (S.J.)
| | - Jia-Yin Wang
- Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, School of Pharmacy, Changzhou University, Changzhou 213164, China;
| | - Yu Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China; (T.X.); (Y.W.); (S.J.)
| | - Shengzhou Jin
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China; (T.X.); (Y.W.); (S.J.)
| | - Yao Tang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA; (Y.T.); (S.Z.); (Q.Y.); (H.L.)
| | - Sai Zhang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA; (Y.T.); (S.Z.); (Q.Y.); (H.L.)
| | - Qingkai Yuan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA; (Y.T.); (S.Z.); (Q.Y.); (H.L.)
| | - Hao Liu
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA; (Y.T.); (S.Z.); (Q.Y.); (H.L.)
| | - Wenxin Yan
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecular, Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China; (W.Y.); (Y.J.)
| | - Yinchun Jiao
- Key Laboratory of Theoretical Organic Chemistry and Functional Molecular, Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China; (W.Y.); (Y.J.)
| | - Xiao-Liang Yang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China; (T.X.); (Y.W.); (S.J.)
| | - Guigen Li
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China; (T.X.); (Y.W.); (S.J.)
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA; (Y.T.); (S.Z.); (Q.Y.); (H.L.)
| |
Collapse
|
5
|
Garg A, Rendina D, Bendale H, Akiyama T, Ojima I. Recent advances in catalytic asymmetric synthesis. Front Chem 2024; 12:1398397. [PMID: 38783896 PMCID: PMC11112575 DOI: 10.3389/fchem.2024.1398397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
Asymmetric catalysis stands at the forefront of modern chemistry, serving as a cornerstone for the efficient creation of enantiopure chiral molecules characterized by their high selectivity. In this review, we delve into the realm of asymmetric catalytic reactions, which spans various methodologies, each contributing to the broader landscape of the enantioselective synthesis of chiral molecules. Transition metals play a central role as catalysts for a wide range of transformations with chiral ligands such as phosphines, N-heterocyclic carbenes (NHCs), etc., facilitating the formation of chiral C-C and C-X bonds, enabling precise control over stereochemistry. Enantioselective photocatalytic reactions leverage the power of light as a driving force for the synthesis of chiral molecules. Asymmetric electrocatalysis has emerged as a sustainable approach, being both atom-efficient and environmentally friendly, while offering a versatile toolkit for enantioselective reductions and oxidations. Biocatalysis relies on nature's most efficient catalysts, i.e., enzymes, to provide exquisite selectivity, as well as a high tolerance for diverse functional groups under mild conditions. Thus, enzymatic optical resolution, kinetic resolution and dynamic kinetic resolution have revolutionized the production of enantiopure compounds. Enantioselective organocatalysis uses metal-free organocatalysts, consisting of modular chiral phosphorus, sulfur and nitrogen components, facilitating remarkably efficient and diverse enantioselective transformations. Additionally, unlocking traditionally unreactive C-H bonds through selective functionalization has expanded the arsenal of catalytic asymmetric synthesis, enabling the efficient and atom-economical construction of enantiopure chiral molecules. Incorporating flow chemistry into asymmetric catalysis has been transformative, as continuous flow systems provide precise control over reaction conditions, enhancing the efficiency and facilitating optimization. Researchers are increasingly adopting hybrid approaches that combine multiple strategies synergistically to tackle complex synthetic challenges. This convergence holds great promise, propelling the field of asymmetric catalysis forward and facilitating the efficient construction of complex molecules in enantiopure form. As these methodologies evolve and complement one another, they push the boundaries of what can be accomplished in catalytic asymmetric synthesis, leading to the discovery of novel, highly selective transformations which may lead to groundbreaking applications across various industries.
Collapse
Affiliation(s)
- Ashna Garg
- Stony Brook University, Department of Chemistry, Stony Brook, NY, United States
| | - Dominick Rendina
- Stony Brook University, Department of Chemistry, Stony Brook, NY, United States
| | - Hersh Bendale
- Stony Brook University, Department of Chemistry, Stony Brook, NY, United States
| | | | - Iwao Ojima
- Stony Brook University, Department of Chemistry, Stony Brook, NY, United States
- Stony Brook University, Institute of Chemical Biology and Drug Discovery, Stony Brook, NY, United States
| |
Collapse
|
6
|
Denhez C, Lameiras P, Berber H. Atropisomerism about aryl-C(sp 3) bonds: chemically driven rotational pathway in cannabidiol derivatives. Org Biomol Chem 2023. [PMID: 38009203 DOI: 10.1039/d3ob01617j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2023]
Abstract
The conformational behaviour arising from the restricted C(sp2)-C(sp3) axis in ortho O-substituted naphthylcyclohexane and naphthylcyclohexene oxide derivatives of cannabidiol was examined by means of VT-NMR experiments and DFT calculations. Atropisomeric compounds with barriers in the range of 91.1 to 95.1 kJ mol-1 were obtained at 298 K. Two possible transition states (TS1 and TS2) were located, one is more stable depending on the chemical modification made on the monoterpene ring close to the pivot bond. Extended analysis of TS structures to previously reported phenyl derivatives bearing the same O-substituent led to similar rotational pathways according to the series: through TS1 in arylcylohexenes and TS2 in arylcyclohexanes. Likewise, conversion of arylcyclohexenes into both series affects the rotation speed by decelerating it, and the nature of the aryl ring seems to have a very minor effect on this phenomenon.
Collapse
Affiliation(s)
- Clément Denhez
- Université de Reims Champagne Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France.
| | - Pedro Lameiras
- Université de Reims Champagne Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France.
| | - Hatice Berber
- Université de Reims Champagne Ardenne, CNRS, ICMR UMR 7312, 51097 Reims, France.
| |
Collapse
|
7
|
Ren X, Duan XY, Li Y, Li J, Qi J. Highly Enantioselective Construction of the Polycyclic Piperazin-2-ones via NHC-Catalyzed [12 + 2] Cycloadditions. Org Lett 2023; 25:7917-7922. [PMID: 37874751 DOI: 10.1021/acs.orglett.3c03171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
NHC-catalyzed diastereoselective and enantioselective [12 + 2] higher-order cycloadditions of 5H-benzo[a]-pyrrolizine-3-carbaldehydes with cyclic sulfonic imines are described. Various optically pure polycyclic piperazin-2-ones were successfully constructed under mild reaction conditions with excellent diastereoselectivities and enantioselectivities. The generated chiral polycyclic piperazin-2-ones could be transformed to planar-chiral nine-membered cyclic amides via squaramide-catalyzed asymmetric ring-expansion reactions.
Collapse
Affiliation(s)
- Xiaojie Ren
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China, and
| | - Xiao-Yong Duan
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China, and
- State Key Laboratory of New Pharmaceutical Preparations and Excipients, College of Chemistry and Materials Science, Hebei University, Baoding 071002, China
| | - Yanting Li
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China, and
| | - Jiahan Li
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China, and
| | - Jing Qi
- College of Chemistry and Materials Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, China, and
- State Key Laboratory of New Pharmaceutical Preparations and Excipients, College of Chemistry and Materials Science, Hebei University, Baoding 071002, China
| |
Collapse
|
8
|
Yang K, Mao Y, Zhang Z, Xu J, Wang H, He Y, Yu P, Song Q. Construction of C-B axial chirality via dynamic kinetic asymmetric cross-coupling mediated by tetracoordinate boron. Nat Commun 2023; 14:4438. [PMID: 37488114 PMCID: PMC10366327 DOI: 10.1038/s41467-023-40164-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 07/14/2023] [Indexed: 07/26/2023] Open
Abstract
Catalytic dynamic kinetic asymmetric transformation (DyKAT) provides a powerful tool to access chiral stereoisomers from racemic substrates. Such transformation has been widely employed on the construction of central chirality, however, the application in axial chirality remains underexplored because its equilibrium of substrate enantiomers is limited to five-membered metalacyclic intermediate. Here we report a tetracoordinate boron-directed dynamic kinetic asymmetric cross-coupling of racemic, configurationally stable 3-bromo-2,1-azaborines with boronic acid derivatives. A series of challenging C-B axially chiral compounds were prepared with generally good to excellent enantioselectivities. Moreover, this transformation can also be extended to prepare atropisomers bearing adjacent C-B and C-C diaxes with excellent diastereo- and enantio-control. The key to the success relies on the rational design of a reversible tetracoordinate boron intermediate, which is supported by theoretical calculations that dramatically reduces the rotational barrier of the original C-B axis and achieves the goal of DyKAT.
Collapse
Affiliation(s)
- Kai Yang
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Yanfei Mao
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Zhihan Zhang
- Department of Chemistry and Shenzhen Grubbs Institute, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Jie Xu
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Hao Wang
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Yong He
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China
| | - Peiyuan Yu
- Department of Chemistry and Shenzhen Grubbs Institute, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
| | - Qiuling Song
- Key Laboratory of Molecule Synthesis and Function Discovery, Fujian Province University, College of Chemistry at Fuzhou University, Fuzhou, Fujian, 350108, China.
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China.
| |
Collapse
|
9
|
Bitsch RS, Jessen NI, Jørgensen KA. Higher-Order Cycloaddition Reactions for the Construction of Polycyclic Aromatic and Polycyclic Heteroaromatic Compounds. Chemistry 2023; 29:e202204008. [PMID: 36592117 DOI: 10.1002/chem.202204008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/02/2023] [Accepted: 01/02/2023] [Indexed: 01/03/2023]
Abstract
Cycloadditions are an important class of reactions in materials science for the construction of polycyclic aromatic and polycyclic heteroaromatic compounds. Recently, cycloadditions have been expanded beyond the "classical" group of cycloadditions involving six π-electrons, and it is now possible to control cycloadditions for an extended number of π-electrons by applying organocatalysis. This novel field of cycloadditions-termed higher-order cycloadditions-allows new synthetic methodologies to construct polycyclic carbo- and heteroaromatic compounds in two or three dimensions. This concept presents higher-order cycloadditions as a method for accessing two- and three-dimensional azulenes and cyclazines, as well as three dimensional indenes, as polycyclic aromatic and polycyclic heteroaromatic compounds.
Collapse
Affiliation(s)
- René S Bitsch
- Department of Chemistry, Aarhus University, 8000, Aarhus C, Denmark
| | | | | |
Collapse
|
10
|
Toda Y, Kooguchi A, Sukegawa K, Kikuchi A, Suga H. Ring-fused hexahydro-1,2,4,5-tetrazines: synthesis, structure, and mechanistic studies on isolable rotational isomers. Chem Commun (Camb) 2023; 59:700-703. [PMID: 36537160 DOI: 10.1039/d2cc06170h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We designed conformationally stable rotational isomers around the C(sp2)-C(sp3) axis at the C3-position of hexahydro-1,2,4,5-tetrazines. Isolation of each rotamer by silica gel column chromatography was successfully achieved at room temperature. The proposed isomerization mechanism of the rotamers was supported by NMR kinetic studies.
Collapse
Affiliation(s)
- Yasunori Toda
- Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1, Wakasato, Nagano, 380-8553, Japan
| | - Airi Kooguchi
- Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1, Wakasato, Nagano, 380-8553, Japan
| | - Kimiya Sukegawa
- Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1, Wakasato, Nagano, 380-8553, Japan
| | - Ayaka Kikuchi
- Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1, Wakasato, Nagano, 380-8553, Japan
| | - Hiroyuki Suga
- Department of Materials Chemistry, Faculty of Engineering, Shinshu University, 4-17-1, Wakasato, Nagano, 380-8553, Japan
| |
Collapse
|
11
|
Jin S, Xu T, Tang Y, Wang JY, Wang Y, Pan J, Zhang S, Yuan Q, Rahman AU, Aquino AJA, Lischka H, Li G. A new chiral phenomenon of orientational chirality, its synthetic control and computational study. Front Chem 2023; 10:1110240. [PMID: 36688043 PMCID: PMC9850238 DOI: 10.3389/fchem.2022.1110240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/19/2022] [Indexed: 01/07/2023] Open
Abstract
A new type of chirality, orientational chirality, consisting of a tetrahedron center and a remotely anchored blocker, has been discovered. The key structural element of this chirality is characterized by multiple orientations directed by a through-space functional group. The multi-step synthesis of orientational chiral targets was conducted by taking advantage of asymmetric nucleophilic addition, Suzuki-Miyaura cross-coupling and Sonogashira coupling. An unprecedented catalytic species showing a five-membered ring consisting of C (sp2)-Br-Pd-C (sp2) bonds was isolated during performing Suzuki-Miyaura cross-coupling. X-ray diffraction analysis confirmed the species structure and absolute configuration of chiral orientation products. Based on X-ray structures, a model was proposed for the new chirality phenomenon to differentiate the present molecular framework from previous others. DFT computational study presented the relative stability of individual orientatiomers. This discovery would be anticipated to result in a new stereochemistry branch and to have a broad impact on chemical, biomedical, and material sciences in the future.
Collapse
Affiliation(s)
- Shengzhou Jin
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Ting Xu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yao Tang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States
| | - Jia-Yin Wang
- Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu, China
| | - Yu Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Junyi Pan
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Sai Zhang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States
| | - Qingkai Yuan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States
| | - Anis Ur Rahman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States
| | - Adelia J. A. Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, TX, United States
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States,*Correspondence: Guigen Li, ; Hans Lischka,
| | - Guigen Li
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China,Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, United States,*Correspondence: Guigen Li, ; Hans Lischka,
| |
Collapse
|
12
|
Portolani C, Centonze G, Righi P, Bencivenni G. Role of Cinchona Alkaloids in the Enantio- and Diastereoselective Synthesis of Axially Chiral Compounds. Acc Chem Res 2022; 55:3551-3571. [PMID: 36475607 PMCID: PMC9774690 DOI: 10.1021/acs.accounts.2c00515] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Asymmetric synthesis using organic catalysts has evolved since it was first realized and defined. Nowadays, it can be considered a valid alternative to transition metal catalysis for synthesizing chiral molecules. According to the literature, the number of asymmetric organocatalytic processes associated with atropisomer synthesis has rapidly increased over the past 10 years because organocatalysis addresses the challenges posed by the most widespread strategies used for preparing axially chiral molecules with satisfactory results.These strategies, useful to prepare a wide range of C-C, C-heteroatom, and N-N atropisomers, vary from kinetic resolution to direct arylation, desymmetrization, and central-to-axial chirality conversion. In this field, our contribution focuses on determining novel methods for synthesizing atropisomers, during which, in most cases, the construction of one or more stereogenic centers other than the stereogenic axis occurred. To efficiently address this challenge, we exploited the ability of catalysts based on a cinchona alkaloid scaffold to realize enantioselective organic transformations. Desymmetrization of N-(2-tert-butylphenyl) maleimides was one of the first strategies that we pursued for preparing C-N atropisomers. The main principle is based on the presence of a rotationally hindered C-N single bond owing to the presence of a large tert-butyl group. Following the peculiar reactivity of this type of substrate as a powerful electrophile and dienophile, we realized several transformations.First, we investigated the vinylogous Michael addition of 3-substituted cyclohexenones, where a stereogenic axis and two contiguous stereocenters were concomitantly and remotely formed and stereocontrolled using a primary amine catalyst. Subsequently, we realized desymmetrization via an organocatalytic Diels-Alder reaction of activated unsaturated ketones that enabled highly atropselective transformation with efficient diastereoselectivity, thereby simultaneously controlling four stereogenic elements. Employing chiral organic bases allowed us to realize efficient desymmetrizations using carbon nucleophiles, such as 1,3-dicarbonyl compounds, cyanoacetates, and oxindoles. These reactions, performed with different types of catalysts, highlighted the versatility of organocatalysis as a powerful strategy for atropselective desymmetrization of pro-axially chiral maleimides.Hereafter, we studied the Friedel-Crafts alkylation of naphthols with indenones, a powerful method for enantioselective synthesis of conformationally restricted diastereoisomeric indanones. We realized the first axially chiral selective Knoevenagel condensation using cinchona alkaloid primary amine as the catalyst. This reaction provided a powerful method to access enantioenriched olefins containing the oxindole core. Subsequently, we initiated an intense program for the computational investigation of the reaction mechanism of our atropselective processes. An understanding of the catalytic activity for vinylogous atropselective desymmetrization as well as of the role played by the acidic cocatalyst used for the experimental work was achieved.Recently, we have garnered interest in the novel frontiers of atropselective synthesis. As observed in recent publications, there is considerable interest in the development of methods for preparing N-N atropisomers, an emerging topic in the field of atropselective synthesis. We focused on the synthesis of hydrazide atropisomers by developing a one-pot sequential catalysis protocol based on two sequential organocatalytic reactions that provided high stereocontrol of two contiguous stereogenic elements.
Collapse
Affiliation(s)
- Chiara Portolani
- Department
of Industrial Chemistry “Toso Montanari,” Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy,Centre
for the Chemical Catalysis−C3, Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy
| | - Giovanni Centonze
- Department
of Industrial Chemistry “Toso Montanari,” Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy,Centre
for the Chemical Catalysis−C3, Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy
| | - Paolo Righi
- Department
of Industrial Chemistry “Toso Montanari,” Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy,Centre
for the Chemical Catalysis−C3, Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy
| | - Giorgio Bencivenni
- Department
of Industrial Chemistry “Toso Montanari,” Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy,Centre
for the Chemical Catalysis−C3, Alma Mater Studiorum−University of Bologna, viale del Risorgimento 4, 40136 Bologna, Italy,
| |
Collapse
|
13
|
Hu P, Liu B, Wang F, Mi R, Li XX, Li X. A Stereodivergent–Convergent Chiral Induction Mode in Atroposelective Access to Biaryls via Rhodium-Catalyzed C–H Bond Activation. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Panjie Hu
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, China
| | - Bingxian Liu
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang 453007, China
| | - Fen Wang
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, China
| | - Ruijie Mi
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, China
| | - Xiao-Xi Li
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, China
| | - Xingwei Li
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, China
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, China
| |
Collapse
|
14
|
Zhu L, Peng H, Guo Y, Che J, Wu JH, Su Z, Wang T. Enantioselective Synthesis of Atropisomeric Biaryl Phosphorus Compounds by Chiral-Phosphonium-Salt-Enabled Cascade Arene Formation. Angew Chem Int Ed Engl 2022; 61:e202202467. [PMID: 35548922 DOI: 10.1002/anie.202202467] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Indexed: 01/26/2023]
Abstract
Axially chiral biaryl monophosphorus molecules, exemplified by atropisomeric 1,1'-biaryl aminophosphines, are significant motifs in numerous chiral ligands/catalysts. Developing efficient methods for preparing phosphorus compounds with these privileged motifs is an important endeavor in synthetic chemistry. Herein, we develop an effective, modular method by a chiral-phosphonium-salt-catalyzed novel cascade between phosphorus-containing nitroolefins and α,α-dicyanoolefins, leading to a great diversity of atropisomeric biaryls bearing phosphorus groups in high yields with excellent stereoselectivities. The reaction features include a Thorpe-type cycloaddition/oxidative hydroxylation/aromatization cascade pathway with a central-to-axial chirality transfer process. Insight gained from our studies is expected to advance general efforts towards the catalytic synthesis of atropisomeric biaryl phosphorus compounds, offering a platform for developing new efficient chiral ligands and catalysts.
Collapse
Affiliation(s)
- Lixiang Zhu
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Heling Peng
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China.,Medical Administration Department, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, 610072, P. R. China
| | - Yan Guo
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Jixing Che
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Jia-Hong Wu
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Zhishan Su
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China
| | - Tianli Wang
- Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, 29 Wangjiang Road, Chengdu, 610064, P. R. China.,Beijing National Laboratory for Molecular Sciences, Beijing, 100190, P. R. China
| |
Collapse
|
15
|
Zeng L, Li J, Cui S. Rhodium‐Catalyzed Atroposelective Click Cycloaddition of Azides and Alkynes. Angew Chem Int Ed Engl 2022; 61:e202205037. [DOI: 10.1002/anie.202205037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Linwei Zeng
- Institute of Drug Discovery and Design College of Pharmaceutical Sciences Zhejiang University 866 Yuhangtang road Hangzhou 310058 China
| | - Jiaming Li
- Institute of Drug Discovery and Design College of Pharmaceutical Sciences Zhejiang University 866 Yuhangtang road Hangzhou 310058 China
| | - Sunliang Cui
- Institute of Drug Discovery and Design College of Pharmaceutical Sciences Zhejiang University 866 Yuhangtang road Hangzhou 310058 China
| |
Collapse
|
16
|
Zhu L, Peng H, Guo Y, Che J, Wu J, Su Z, Wang T. Enantioselective Synthesis of Atropisomeric Biaryl Phosphorus Compounds by Chiral‐Phosphonium‐Salt‐Enabled Cascade Arene Formation. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202202467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Lixiang Zhu
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Heling Peng
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
- Medical Administration Department Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital Chengdu 610072 P. R. China
| | - Yan Guo
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Jixing Che
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Jia‐Hong Wu
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Zhishan Su
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
| | - Tianli Wang
- Key Laboratory of Green Chemistry & Technology of Ministry of Education College of Chemistry Sichuan University 29 Wangjiang Road Chengdu 610064 P. R. China
- Beijing National Laboratory for Molecular Sciences Beijing 100190 P. R. China
| |
Collapse
|
17
|
Zeng L, Li J, Cui S. Rhodium‐Catalyzed Atroposelective Click Cycloaddition of Azides and Alkynes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202205037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Linwei Zeng
- Institute of Drug Discovery and Design College of Pharmaceutical Sciences Zhejiang University 866 Yuhangtang road Hangzhou 310058 China
| | - Jiaming Li
- Institute of Drug Discovery and Design College of Pharmaceutical Sciences Zhejiang University 866 Yuhangtang road Hangzhou 310058 China
| | - Sunliang Cui
- Institute of Drug Discovery and Design College of Pharmaceutical Sciences Zhejiang University 866 Yuhangtang road Hangzhou 310058 China
| |
Collapse
|
18
|
Jin S, Wang Y, Tang Y, Wang JY, Xu T, Pan J, Zhang S, Yuan Q, Rahman AU, McDonald JD, Wang GQ, Li S, Li G. Orientational Chirality, Its Asymmetric Control, and Computational Study. RESEARCH 2022. [DOI: 10.34133/research.0012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Orientational chirality was discovered and characterized by a C(sp)–C(sp
3
) axis-anchored chiral center and a remotely anchored blocker. X-ray structural analysis proved that orientatiomers are stabilized by through-space functional groups, making it possible for 1
R
- or
S
-chiral center to exhibit 3 orientational isomers simply by rotating operations. A new model system was proposed, fundamentally different from the traditional Felkin–Ahn-type or Cram-type models. In these traditional models, chiral C(sp
3
) center and blocking C(sp
2
) carbons are connected adjacently, and there exist 6 energy barriers during rotating along the C(sp
2
)−C(sp
3
) axis. In comparison, the present orientational chirality model shows that a chiral C(sp)–C(sp
3
) carbon is remotely located from a blocking group. Thus, it is focused on the steric dialog between a chiral C(sp
3
) center and a remotely anchored functional group. There exist 3 energy barriers for either (
R
)– or (
S
)–C(sp)–C(sp
3
) stereogenicity in the new model. Chiral amide auxiliary was proven to be an excellent chiral auxiliary in controlling rotations of orientatiomers to give complete stereoselectivity. The asymmetric synthesis of individual orientatiomers was conducted via multistep synthesis by taking advantage of the Suzuki–Miyaura cross-coupling and Sonogashira coupling reactions. Density functional theory computational study presented optimized conformers and relative energies for individual orientatiomers. This discovery would be anticipated to result in a new stereochemistry topic and have a broad impact on chemical, biomedical, and material sciences in the future.
Collapse
Affiliation(s)
- Shengzhou Jin
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Yu Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Yao Tang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Jia-Yin Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
- Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu 213164, China
| | - Ting Xu
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Junyi Pan
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Sai Zhang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Qiankai Yuan
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Anis Ur Rahman
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - James D. McDonald
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| | - Guo-Qiang Wang
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Shuhua Li
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Guigen Li
- School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061, USA
| |
Collapse
|
19
|
Li A, Gao Y, Lu JB, Chen ZC, Du W, Chen YC. Asymmetric higher-order [10+n] cycloadditions of palladium-containing 10π-cycloaddends. Chem Sci 2022; 13:9265-9270. [PMID: 36092999 PMCID: PMC9384823 DOI: 10.1039/d2sc02985e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 07/14/2022] [Indexed: 11/21/2022] Open
Abstract
We uncovered an asymmetric higher-order [10 + 2] cycloaddition reaction between diverse activated alkenes and a new type of π-allylpalladium complex-containing dipole-type 10π-cycloaddend, which was generated in situ from 2-methylene-1-indanols via a dehydrative insertion and deprotonation strategy under double activation of Pd(0) and phosphoric acid. A similar strategy was applied to an asymmetric higher-order [10 + 8] cycloaddition reaction or [10 + 4] cycloaddition reaction by using a heptafulvene derivative or a cyclic enone, respectively, as the acceptor. A variety of polycyclic frameworks imbedding an indene core were generally furnished in moderate to excellent yields with high levels of enantioselectivity by employing a newly designed chiral phosphoramidite ligand. A type of π-allylpalladium complex-containing 10π-cycloaddend generated from 2-methylene-1-indanols under double activation of Pd(0) and phosphoric acid undergoes asymmetric higher-order [10 + 2] cycloadditions with diverse activated alkenes.![]()
Collapse
Affiliation(s)
- Ao Li
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Yang Gao
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Jian-Bin Lu
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Zhi-Chao Chen
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Wei Du
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
| | - Ying-Chun Chen
- Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry and Sichuan Province, Sichuan Research Center for Drug Precision Industrial Technology, West China School of Pharmacy, Sichuan University Chengdu 610041 China +86 28 85502609
- College of Pharmacy, Third Military Medical University Shapingba, Chongqing 400038 China
| |
Collapse
|