1
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Ande C, Crich D. Stereodirecting Effect of Esters at the 4-Position of Galacto- and Glucopyranosyl Donors: Effect of 4- C-Methylation on Side-Chain Conformation and Donor Reactivity, and Influence of Concentration and Stoichiometry on Distal Group Participation. J Org Chem 2023; 88:13883-13893. [PMID: 37677151 PMCID: PMC10563135 DOI: 10.1021/acs.joc.3c01496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Indexed: 09/09/2023]
Abstract
When generated in a mass spectrometer bridged bicyclic 1,3-dioxenium ions derived from 4-O-acylgalactopyranosyl, donors can be observed by infrared spectroscopy at cryogenic temperatures, but they are not seen in the solution phase in contrast to the fused bicyclic 1,3-dioxalenium ions of neighboring group participation. The inclusion of a 4-C-methyl group into a 4-O-benzoyl galactopyranosyl donor enables nuclear magnetic resonance observation of the bicyclic ion arising from participation by the distal ester, with the methyl group influence attributed to ester ground state conformation destabilization. We show that a 4-C-methyl group also influences the side-chain conformation, enforcing a gauche,trans conformation in gluco and galactopyranosides. Competition experiments reveal that the 4-C-methyl group has only a minor influence on the rate of reaction of 4-O-benzoyl or 4-O-benzyl-galacto and glucopyranosyl donors and, consequently, that participation by the distal ester does not result in kinetic acceleration (anchimeric assistance). We demonstrate that the stereoselectivity of the 4-O-benzoyl-4-C-methyl galactopyranosyl donor depends on reaction concentration and additive (diphenyl sulfoxide) stoichiometry and hence that participation by the distal ester is a borderline phenomenon in competition with standard glycosylation mechanisms. An analysis of a recent paper affirming participation by a remote pivalate ester is presented with alternative explanations for the observed phenomena.
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Affiliation(s)
- Chennaiah Ande
- Department
of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
| | - David Crich
- Department
of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Department
of Chemistry, University of Georgia, 302 East Campus Road, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend
Road, Athens, Georgia 30602, United States
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2
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Bakhshandeh A, Levin Y. Charge fluctuations in charge-regulated systems: dependence on statistical ensemble. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:65. [PMID: 37522995 DOI: 10.1140/epje/s10189-023-00325-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/18/2023] [Indexed: 08/01/2023]
Abstract
We investigate charge regulation of nanoparticles in concentrated suspensions, focusing on the effect of different statistical ensembles. We find that the choice of ensemble does not affect the mean charge of nanoparticles, but significantly alters the magnitude of its fluctuation. Specifically, we compared the behaviors of colloidal charge fluctuations in the semi-grand canonical and canonical ensembles and identified significant differences between the two. The choice of ensemble-whether the system is isolated or is in contact with a reservoir of acid and salt-will, therefore, affect the Kirkwood-Shumaker fluctuation-induced force inside concentrated suspensions. Our results emphasize the importance of selecting an appropriate ensemble that accurately reflects the experimental conditions when studying fluctuation-induced forces between polyelectrolytes, proteins, and colloidal particles in concentrated suspensions.
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Affiliation(s)
- Amin Bakhshandeh
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970, Brazil
| | - Yan Levin
- Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, 91501-970, Brazil.
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3
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Lu Z, Liu D, Wei P, Yi T. Activated aggregation strategies to construct size-increasing nanoparticles for cancer therapy. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2023; 15:e1848. [PMID: 36039701 DOI: 10.1002/wnan.1848] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/11/2022] [Accepted: 08/01/2022] [Indexed: 11/06/2022]
Abstract
The development of novel therapeutic strategies and modalities for tumors is still one of the important areas of current scientific research. Low permeability and short residence time of drugs in solid tumor areas are important reasons for the low efficiency of existing therapeutic strategies. Typically, nanoparticles with large size displayed enhanced residence time but low permeability. Therefore, to prolong the retention time of materials in solid tumors, size-increasing strategies have been developed to directly generate large-scale nanoparticles using small molecular compounds or increase the size of small nanoparticles in solid tumor areas. In this review, we summarize recently reported activatable aggregation systems that could be activated by cancer-related substances for cancer therapy and classify them by the mechanisms that lead to aggregation. In the end, we propose some potential challenges briefly from the view of our opinion. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.
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Affiliation(s)
- Zhenni Lu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, China
| | - Dongya Liu
- Department of Chemistry, Fudan University, Shanghai, China
| | - Peng Wei
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, China
| | - Tao Yi
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Shanghai Engineering Research Center of Nano-Biomaterials and Regenerative Medicine, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, China
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4
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Mohammadi H, Azami SM, Rafii-Tabar H. Density functional theory computation of the intermolecular interactions of Al 2@C 24 and Al 2@Mg 12O 12 semiconducting quantum dots conjugated with the glycine tripeptide. RSC Adv 2023; 13:9824-9837. [PMID: 36998517 PMCID: PMC10043880 DOI: 10.1039/d3ra01154b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
The nature of intermolecular forces within semiconductor quantum dot systems can determine various physicochemical properties, as well as their functions, in nanomedical applications. The purpose of this study has been to investigate the nature of the intermolecular forces operating between Al2@C24 and Al2@Mg12O12 semiconducting quantum dots and the glycine tripeptide (GlyGlyGly), and also consider whether permanent electric dipole–dipole interactions play a significant role vis-à-vis these molecular systems. The energy computations, including the Keesom and the total electronic interactions and the energy decomposition, together with the quantum topology analyses were performed. Our results demonstrate that no significant correlation is found between the magnitude and orientation of the electrical dipole moments, and the interaction energy of the Al2@C24 and Al2@Mg12O12 with GlyGlyGly tripeptide. The Pearson correlation coefficient test revealed a very weak correlation between the quantum and the Keesom interaction energies. Apart from the quantum topology analyses, the energy decomposition consideration confirmed that the dominant share of the interaction energies was associated with the electrostatic interactions, yet both the steric and the quantum effects also made appreciable contributions. We conclude that, beside the electrical dipole–dipole interactions, other prominent intermolecular forces, such as the polarization attraction, the hydrogen bond, and the van der Waals interactions can also influence the interaction energy of the system. The findings of this study can be utilized in several areas in the field of nanobiomedicine, including the rational design of cell-penetrating and intracellular drug delivery systems using semiconducting quantum dots functionalized with a peptide. The nature of intermolecular forces within semiconducting quantum dot systems can determine various physicochemical properties, as well as their functions, in nanomedical applications.![]()
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Affiliation(s)
- Hadi Mohammadi
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shahid Beheshti University of Medical SciencesTehranIran
| | - S. M. Azami
- Department of Chemistry, Faculty of Sciences, Yasouj UniversityYasoujIran
| | - Hashem Rafii-Tabar
- Department of Medical Physics and Biomedical Engineering, School of Medicine, Shahid Beheshti University of Medical SciencesTehranIran
- The Physics Branch of the Academy of Sciences of IranTehranIran
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5
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Kazi I, Nandy A, Selvam R, Sekar G. Halogen Bond-Activated Visible-Light-Mediated Regioselective C-H Arylation of 2-Phenylimidazo-[1,2- a]pyridines. J Org Chem 2022; 87:12323-12333. [PMID: 36065525 DOI: 10.1021/acs.joc.2c01548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An efficient method for transition metal-free halogen bond-assisted regioselective C-H arylation of 2-phenylimidazo-[1,2-a]pyridines under visible-light condition has been developed. The halogen bond between an aryl halide and base KOtBu initiates an electron transfer process and generates an aryl radical, which catalyzes its coupling with 2-phenylimidazo-[1,2-a]pyridines to give arylated products in good yield. Several control experiments, density functional theory calculations, and ultraviolet-visible analysis indicate the presence of a halogen bond between an aryl halide and KOtBu. This methodology has been successfully utilized to synthesize antileishmanial agents.
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Affiliation(s)
- Imran Kazi
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600 036, India
| | - Anuradha Nandy
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600 036, India
| | - Raji Selvam
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600 036, India
| | - Govindasamy Sekar
- Department of Chemistry, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600 036, India
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6
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Ramdular A, Woerpel KA. Diastereoselective Substitution Reactions of Acyclic β-Alkoxy Acetals via Electrostatically Stabilized Oxocarbenium Ion Intermediates. Org Lett 2022; 24:3217-3222. [PMID: 35446592 PMCID: PMC9817112 DOI: 10.1021/acs.orglett.2c01004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Substitution reactions of acyclic β-alkoxy acetals proceeded with generally high diastereoselectivities (>90:10) to form the anti product. Mechanistic experiments supplemented with computational studies suggest that, upon activation of the acetal, the resulting oxocarbenium ion is electrostatically stabilized by the β-alkoxy group. This stabilization defines the conformation of the reactive intermediate, which can be attacked preferentially from the more exposed face, leading to the observed products.
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Affiliation(s)
- Amanda Ramdular
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 (USA)
| | - K. A. Woerpel
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003 (USA),Corresponding Author: K. A. Woerpel – Department of Chemistry, New York University, New York, New York 10003, United States;
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7
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Hernández D, Porras M, Boto A. Structural diversity using amino acid "Customizable Units": conversion of hydroxyproline (Hyp) into nitrogen heterocycles. Amino Acids 2022; 54:955-966. [PMID: 35414005 PMCID: PMC9213323 DOI: 10.1007/s00726-022-03159-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/20/2022] [Indexed: 12/01/2022]
Abstract
The ability of amino acid “customizable units” to generate structural diversity is illustrated by the conversion of 4-hydroxyproline (Hyp) units into a variety of nitrogen heterocycles. After a first common step, where the unit underwent a one-pot decarboxylation–alkylation reaction to afford 2-alkylpyrrolidines with high stereoselectivity, a divergent step was carried out. Thus, the deprotected 4-hydroxy group was used either to initiate a radical scission that afforded aliphatic β-amino aldehydes, or to carry out an elimination reaction, to give 2-alkyl-2,5-dihydro-1H-pyrroles. In the first case, the amines underwent a tandem reductive amination–cyclization to afford β-amino-δ-lactams, an efficient rigidifying unit in peptides. Different lactam N-substituents, such as alkylamines, peptides, and alkenyl chains suitable for olefin metathesis were introduced this way. In the second case, the pyrrole derivatives were efficiently converted into alkaloid and iminosugar derivatives in good global yields and with excellent stereoselectivity.
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Affiliation(s)
- Dácil Hernández
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Francisco Sánchez, 3, 38206, La Laguna, Tenerife, Spain.
| | - Marina Porras
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Francisco Sánchez, 3, 38206, La Laguna, Tenerife, Spain
| | - Alicia Boto
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Francisco Sánchez, 3, 38206, La Laguna, Tenerife, Spain.
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8
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Turner JA, Adrianov T, Zakaria MA, Taylor MS. Effects of Configuration and Substitution on C-H Bond Dissociation Enthalpies in Carbohydrate Derivatives: A Systematic Computational Study. J Org Chem 2021; 87:1421-1433. [PMID: 34964632 DOI: 10.1021/acs.joc.1c02725] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional theory was used to calculate C-H bond dissociation enthalpies (BDEs) at each position of a diverse collection of pyranosides and furanosides differing in relative configuration and substitution patterns. A detailed analysis of the resulting data set (186 BDEs, calculated at the M06-2X/def2-TZVP level of theory) highlights the ways in which stereoelectronic effects, conformational properties, and noncovalent interactions can influence the strengths of C-H bonds in carbohydrates. The results point toward opportunities to alter the radical reactivity of carbohydrate derivatives by variation of their stereochemical configuration or the positions and types of protective groups.
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Affiliation(s)
- Julia A Turner
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
| | - Timur Adrianov
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
| | - Mia Ahed Zakaria
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
| | - Mark S Taylor
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6 Canada
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9
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Omar CA, Fernando SP. Nucleophilic substitution at the anomeric position of furanose carbohydrates. The case of the C-allylations. Carbohydr Res 2021; 510:108441. [PMID: 34700220 DOI: 10.1016/j.carres.2021.108441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/31/2021] [Accepted: 09/07/2021] [Indexed: 11/28/2022]
Abstract
Taking advantage of the locked conformation of cyclic furanose form, carbohydrate derivatives have been transformed into relevant tetrahydrofuran moieties through a chemical operation commonly known as C-glycosylation reaction. Consequently, a large number of total synthesis of naturally occurring products containing this heterocycle have been accomplished by applying this reaction. In this regard, the C-allylation reaction of furanose carbohydrates provides flexible routes for stereoselective anomeric functionalization by incorporating an allyl group, which is eventually re-functionalized into advanced natural product intermediates. Therefore, this mini review deals with the description of the origin of the stereoselectivity and synthetic applications of this type of glycosylation reaction, which can be also called as: "Nucleophilic Substitution at the Anomeric Position", conducted by various research groups including our own group.
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Affiliation(s)
- Cortezano-Arellano Omar
- Instituto de Ciencias Básicas, Universidad Veracruzana, Luis Castelazo Ayala, Col. Industrial Ánimas, 91190, Xalapa, Ver., Mexico
| | - Sartillo-Piscil Fernando
- Centro de Investigación de la Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla (BUAP), 14 Sur Esq. San Claudio, Col. San Manuel, 72570, Puebla, Mexico.
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10
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Abstract
With a view to reducing the notorious complexity and irreproducibility of glycosylation reactions, 12 guidelines for the choice of concentration, temperature, and counterions are adumbrated.
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Affiliation(s)
- Peter R. Andreana
- Department of Chemistry
and Biochemistry and School of Green Chemistry and Engineering, University of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United States
| | - David Crich
- Department of Pharmaceutical and Biomedical
Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Department
of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, 315 Riverbend
Road, Athens, Georgia 30602, United States
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11
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Quirke JCK, Crich D. GH47 and Other Glycoside Hydrolases Catalyze Glycosidic Bond Cleavage with the Assistance of Substrate Super-arming at the Transition State. ACS Catal 2021; 11:10308-10315. [PMID: 34777906 PMCID: PMC8579916 DOI: 10.1021/acscatal.1c02750] [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] [Indexed: 11/28/2022]
Abstract
Super-armed glycosyl donors, whose substituents are predominantly held in pseudoaxial positions, exhibit strongly increased reactivity in glycosylation through significant stabilization of oxocarbenium-like transition states. Examination of X-ray crystal structures reveals that the GH47 family of glycoside hydrolases have evolved so as to distort their substrates away from the ground state conformation in such a manner as to present multiple C-O bonds in pseudoaxial positions and so benefit from conformational super-arming of their substrates, thereby enhancing catalysis. Through analysis of literature mutagenic studies, we show that a suitably placed aromatic residue in GHs 6 and 47 sterically enforces super-armed conformations on their substrates. GH families 45, 81, and 134 on the other hand impose conformational super-arming on their substrates, by maintaining the more active ring conformation through hydrogen bonding rather than steric interactions. The recognition of substrate super-arming by select GH families provides a further parallel with synthetic carbohydrate chemistry and nature and opens further avenues for the design of improved glycosidase inhibitors.
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Affiliation(s)
- Jonathan C K Quirke
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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12
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Quirke JCK, Crich D. Side Chain Conformation Restriction in the Catalysis of Glycosidic Bond Formation by Leloir Glycosyltransferases, Glycoside Phosphorylases, and Transglycosidases. ACS Catal 2021; 11:5069-5078. [PMID: 34367723 PMCID: PMC8336929 DOI: 10.1021/acscatal.1c00896] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Carbohydrate side chain conformation is an important factor in the control of reactivity at the anomeric center, ie, in the making and breaking of glycosidic bonds, whether chemically or, for hydrolysis, by glycoside hydrolases. In nature glycosidic bond formation is catalyzed out by glycosyltransferases (GTs), glycoside phosphoryases, and transglycosidases. By analysis of 118 crystal structures of sugar nucleotide dependent (Leloir) GTs, 136 crystal structures of glycoside phosphorylases, and 54 crystal structures of transglycosidases bound to hexopyranosides or their analogs at the donor site (-1 site), we determined that most enzymes that catalyze glycoside synthesis, be they GTs, glycoside phosphorylases or transglycosidases, restrict their substrate side chains to the most reactive gauche,gauche (gg) conformation to achieve maximum stabilization of the oxocarbenium ion-like transition state for glycosyl transfer. The galactose series deviates from this trend, with α-galactosyltransferases preferentially restricting their substrates to the second-most reactive gauche,trans (gt) conformation, and β-galactosyltransferases favoring the least reactive trans,gauche (tg) conformation. This insight will help progress the design and development of improved, conformationally-restricted GT inhibitors that take advantage of these inherent side chain preferences.
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Affiliation(s)
- Jonathan C. K. Quirke
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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13
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Arcile G, Retailleau P, Ouazzani J, Betzer J. Total Synthesis of the Fungal Metabolite Trienylfuranol A through Nucleophilic Diastereodivergent Additions to Oxocarbenium Ions. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Guillaume Arcile
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 Université Paris-Saclay 1 avenue de la Terrasse 91198 Gif-sur-Yvette Cedex France
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 Université Paris-Saclay 1 avenue de la Terrasse 91198 Gif-sur-Yvette Cedex France
| | - Jamal Ouazzani
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 Université Paris-Saclay 1 avenue de la Terrasse 91198 Gif-sur-Yvette Cedex France
| | - Jean‐Francois Betzer
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 Université Paris-Saclay 1 avenue de la Terrasse 91198 Gif-sur-Yvette Cedex France
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14
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Crich D. En Route to the Transformation of Glycoscience: A Chemist's Perspective on Internal and External Crossroads in Glycochemistry. J Am Chem Soc 2021; 143:17-34. [PMID: 33350830 PMCID: PMC7856254 DOI: 10.1021/jacs.0c11106] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Carbohydrate chemistry is an essential component of the glycosciences and is fundamental to their progress. This Perspective takes the position that carbohydrate chemistry, or glycochemistry, has reached three crossroads on the path to the transformation of the glycosciences, and illustrates them with examples from the author's and other laboratories. The first of these potential inflexion points concerns the mechanism of the glycosylation reaction and the role of protecting groups. It is argued that the experimental evidence supports bimolecular SN2-like mechanisms for typical glycosylation reactions over unimolecular ones involving stereoselective attack on naked glycosyl oxocarbenium ions. Similarly, it is argued that the experimental evidence does not support long-range stereodirecting participation of remote esters through bridged bicyclic dioxacarbenium ions in organic solution in the presence of typical counterions. Rational design and improvement of glycosylation reactions must take into account the roles of the counterion and of concentration. A second crossroads is that between mainstream organic chemistry and glycan synthesis. The case is made that the only real difference between glycan and organic synthesis is the formation of C-O rather than C-C bonds, with diastereocontrol, strategy, tactics, and elegance being of critical importance in both areas: mainstream organic chemists should feel comfortable taking this fork in the road, just as carbohydrate chemists should traveling in the opposite direction. A third crossroads is that between carbohydrate chemistry and medicinal chemistry, where there are equally many opportunities for traffic in either direction. The glycosciences have advanced enormously in the past decade or so, but creativity, input, and ingenuity of scientists from all fields is needed to address the many sophisticated challenges that remain, not the least of which is the development of a broader and more general array of stereospecific glycosylation reactions.
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Affiliation(s)
- David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
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15
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Hernández D, Carro C, Boto A. "Doubly Customizable" Unit for the Generation of Structural Diversity: From Pure Enantiomeric Amines to Peptide Derivatives. J Org Chem 2021; 86:2796-2809. [PMID: 33433228 DOI: 10.1021/acs.joc.0c02751] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Readily available, low-cost 4R-hydroxy-l-proline (Hyp) is introduced as a "doubly customizable" unit for the generation of libraries of structurally diverse compounds. Hyp can be cleaved at two points, followed by the introduction of new functionalities. In the first cycle, the removal and replacement of the carboxylic group are carried out, followed (second cycle) by the scission of the 4,5-position and manipulation of the resulting chains. In this way, three new chains are generated and can be transformed independently to afford a diversity of products with tailored substituents, such as β-amino aldehydes, diamines, β-amino acid derivatives, including N-alkylated ones, or modified peptides. Many of these products are high-profit compounds but, in spite of their commercial value, are still scarce. Moreover, the process takes place with stereochemical control, and either pure R or S isomers can be obtained with small variations of the synthetic route.
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Affiliation(s)
- Dacil Hernández
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Fco. Sánchez, 3, 38206 La Laguna, Tenerife, Spain
| | - Carmen Carro
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Fco. Sánchez, 3, 38206 La Laguna, Tenerife, Spain.,BIOSIGMA, Antonio Domínguez Alfonso 16, 38003 Santa Cruz de Tenerife, Tenerife, Spain
| | - Alicia Boto
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Fco. Sánchez, 3, 38206 La Laguna, Tenerife, Spain
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16
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Jeanneret RA, Johnson SE, Galan MC. Conformationally Constrained Glycosyl Donors as Tools to Control Glycosylation Outcomes. J Org Chem 2020; 85:15801-15826. [DOI: 10.1021/acs.joc.0c02045] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Robin A. Jeanneret
- School of Chemistry, University of Bristol, Cantock’s
Close, Bristol BS8 1TS, United Kingdom
| | - Simon E. Johnson
- School of Chemistry, University of Bristol, Cantock’s
Close, Bristol BS8 1TS, United Kingdom
| | - M. Carmen Galan
- School of Chemistry, University of Bristol, Cantock’s
Close, Bristol BS8 1TS, United Kingdom
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17
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Onobun E, Crich D. Synthesis of 3-Deoxy-d- manno-oct-2-ulosonic Acid (KDO) and Pseudaminic Acid C-Glycosides. J Org Chem 2020; 85:16035-16042. [PMID: 32897074 DOI: 10.1021/acs.joc.0c01838] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preparation of glycosyl dibutyl phosphates in the 3-deoxy-d-manno-oct-2-ulosonic acid (KDO) and pseudaminic acid series and their application to the formation of C-glycosides are described. Both donors were obtained from the corresponding thioglycosides by treatment with dibutylphosphoric acid and N-iodosuccinimide. As with the thioglycosides, both donors adopted very predominantly the strongly electron-withdrawing tg conformation of their side chains, which is reflected in the excellent equatorial selectivity of both donors in the formation of exemplary O-glycosides. With respect to C-glycoside formation on the other hand, contrasting results were observed: the KDO donor was either relatively unselective or selective for the formation of the axial C-glycoside, while the pseudaminic acid donor was selective for the formation of the equatorial C-glycoside. These observations are rationalized in terms of the greater electron-withdrawing ability of the azides in the pseudaminic acid donor compared to the corresponding acetoxy groups in the KDO series, resulting in a reaction through tighter ion pairs even at the SN1 end of the general glycosylation mechanism. The contrast in the axial versus the equatorial selectivity between C- and O-glycosylation cautions against the extrapolation of models for SN1-type glycosylation with weak nucleophiles for the explanation of O-glycosylation.
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Affiliation(s)
- Emmanuel Onobun
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States.,Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States.,Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, Georgia 30602, United States.,Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States.,Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, United States
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18
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Hettikankanamalage AA, Lassfolk R, Ekholm FS, Leino R, Crich D. Mechanisms of Stereodirecting Participation and Ester Migration from Near and Far in Glycosylation and Related Reactions. Chem Rev 2020; 120:7104-7151. [PMID: 32627532 PMCID: PMC7429366 DOI: 10.1021/acs.chemrev.0c00243] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review is the counterpart of a 2018 Chemical Reviews article (Adero, P. O.; Amarasekara, H.; Wen, P.; Bohé, L.; Crich, D. Chem. Rev. 2018, 118, 8242-8284) that examined the mechanisms of chemical glycosylation in the absence of stereodirecting participation. Attention is now turned to a critical review of the evidence in support of stereodirecting participation in glycosylation reactions by esters from either the vicinal or more remote positions. As participation by esters is often accompanied by ester migration, the mechanism(s) of migration are also reviewed. Esters are central to the entire review, which accordingly opens with an overview of their structure and their influence on the conformations of six-membered rings. Next the structure and relative energetics of dioxacarbeniun ions are covered with emphasis on the influence of ring size. The existing kinetic evidence for participation is then presented followed by an overview of the various intermediates either isolated or characterized spectroscopically. The evidence supporting participation from remote or distal positions is critically examined, and alternative hypotheses for the stereodirecting effect of such esters are presented. The mechanisms of ester migration are first examined from the perspective of glycosylation reactions and then more broadly in the context of partially acylated polyols.
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Affiliation(s)
- Asiri A. Hettikankanamalage
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
| | - Robert Lassfolk
- Johan Gadolin Process Chemistry Centre, Laboratory of Molecular Science and Technology, Åbo Akademi University, 20500 Åbo, Finland
| | - Filip S. Ekholm
- Department of Chemistry, University of Helsinki, A. I. Virtasen aukio 1, 00014 Helsinki, Finland
| | - Reko Leino
- Johan Gadolin Process Chemistry Centre, Laboratory of Molecular Science and Technology, Åbo Akademi University, 20500 Åbo, Finland
| | - David Crich
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia, 250 West Green Street, Athens, GA 30602, USA
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602, USA
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
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19
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Santana AG, Montalvillo-Jiménez L, Díaz-Casado L, Corzana F, Merino P, Cañada FJ, Jiménez-Osés G, Jiménez-Barbero J, Gómez AM, Asensio JL. Dissecting the Essential Role of Anomeric β-Triflates in Glycosylation Reactions. J Am Chem Soc 2020; 142:12501-12514. [DOI: 10.1021/jacs.0c05525] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
| | | | | | - Francisco Corzana
- Departamento Quı́mica and Centro de Investigación en Sı́ntesis Quı́mica, Universidad de La Rioja, 26006 Rioja, Spain
| | - Pedro Merino
- Instituto de Biocomputación y Fı́sica de Sistemas Complejos (BIFI), Universidad de Zaragoza, 50018 Zaragoza, Spain
| | | | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC-bioGUNE), 48160 Derio, Spain
| | - Jesús Jiménez-Barbero
- Center for Cooperative Research in Biosciences (CIC-bioGUNE), 48160 Derio, Spain
- Ikerbasque Basque Foundation for Science, 48013 Bilbao, Basque
| | - Ana M. Gómez
- Instituto de Quı́mica Orgánica (IQOG-CSIC), 28006 Madrid, Spain
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20
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de Kleijne FFJ, Moons SJ, White PB, Boltje TJ. C-2 auxiliaries for stereoselective glycosylation based on common additive functional groups. Org Biomol Chem 2020; 18:1165-1184. [PMID: 31984407 DOI: 10.1039/c9ob02700a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The stereoselective introduction of the glycosidic bond is one of the main challenges in chemical oligosaccharide synthesis. Stereoselective glycosylation can be achieved using neighbouring group participation of a C-2 auxiliary or using additives, for example. Both methods aim to generate a defined reactive intermediate that reacts in a stereoselective manner with alcohol nucleophiles. This inspired us to develop new C-2 auxiliaries based on commonly used additive functionalities such as ethers, phosphine oxides and tertiary amides. Good 1,2-trans-selectivity was observed for the phosphine oxide and amide-based auxiliaries expanding the toolbox with new auxiliaries for stereoselective glycosylation reactions.
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Affiliation(s)
| | - Sam J Moons
- Institute for molecules and materials, Nijmegen, 6525AJ, Netherlands.
| | - Paul B White
- Institute for molecules and materials, Nijmegen, 6525AJ, Netherlands.
| | - Thomas J Boltje
- Institute for molecules and materials, Nijmegen, 6525AJ, Netherlands.
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21
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Bartolo ND, Read JA, Valentín EM, Woerpel KA. Reactions of Allylmagnesium Reagents with Carbonyl Compounds and Compounds with C═N Double Bonds: Their Diastereoselectivities Generally Cannot Be Analyzed Using the Felkin-Anh and Chelation-Control Models. Chem Rev 2020; 120:1513-1619. [PMID: 31904936 PMCID: PMC7018623 DOI: 10.1021/acs.chemrev.9b00414] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This review describes the additions of allylmagnesium reagents to carbonyl compounds and to imines, focusing on the differences in reactivity between allylmagnesium halides and other Grignard reagents. In many cases, allylmagnesium reagents either react with low stereoselectivity when other Grignard reagents react with high selectivity, or allylmagnesium reagents react with the opposite stereoselectivity. This review collects hundreds of examples, discusses the origins of stereoselectivities or the lack of stereoselectivity, and evaluates why selectivity may not occur and when it will likely occur.
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Affiliation(s)
- Nicole D. Bartolo
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
| | - Jacquelyne A. Read
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
- Department of Chemistry, University of Utah, 315 South 1400
East, Salt Lake City, UT 84112, USA
| | - Elizabeth M. Valentín
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
- Department of Chemistry, Susquehanna University, 514
University Avenue, Selinsgrove, PA 17870, USA
| | - K. A. Woerpel
- Department of Chemistry, New York University, 100
Washington Square East, New York, NY 10003, USA
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22
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Montalvillo-Jiménez L, Santana AG, Corzana F, Jiménez-Osés G, Jiménez-Barbero J, Gómez AM, Asensio JL. Impact of Aromatic Stacking on Glycoside Reactivity: Balancing CH/π and Cation/π Interactions for the Stabilization of Glycosyl-Oxocarbenium Ions. J Am Chem Soc 2019; 141:13372-13384. [PMID: 31390207 DOI: 10.1021/jacs.9b03285] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Carbohydrate/aromatic stacking represents a recurring key motif for the molecular recognition of glycosides, either by protein binding domains, enzymes, or synthetic receptors. Interestingly, it has been proposed that aromatic residues might also assist in the formation/cleavage of glycosidic bonds by stabilizing positively charged oxocarbenium-like intermediates/transition states through cation/π interactions. While the significance of aromatic stacking on glycoside recognition is well stablished, its impact on the reactivity of glycosyl donors is yet to be explored. Herein, we report the first experimental study on this relevant topic. Our strategy is based on the design, synthesis, and reactivity evaluation of a large number of model systems, comprising a wide range of glycosidic donor/aromatic complexes. Different stacking geometries and dynamic features, anomeric leaving groups, sugar configurations, and reaction conditions have been explicitly considered. The obtained results underline the opposing influence exerted by van der Waals and Coulombic forces on the reactivity of the carbohydrate/aromatic complex: depending on the outcome of this balance, aromatic platforms can indeed exert a variety of effects, stretching from reaction inhibition all the way to rate enhancements. Although aromatic/glycosyl cation contacts are highly dynamic, the conclusions of our study suggest that aromatic assistance to glycosylation processes must indeed be feasible, with far reaching implications for enzyme engineering and organocatalysis.
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Affiliation(s)
| | - Andrés G Santana
- Instituto de Química Orgánica (IQOG-CSIC) , Juan de la Cierva 3 , 28006 Madrid , Spain
| | - Francisco Corzana
- Departamento Quı́mica and Centro de Investigación en Sı́ntesis Quı́mica , Universidad de La Rioja , 26006 Logroño , Spain
| | - Gonzalo Jiménez-Osés
- Center for Cooperative Research in Biosciences (CIC-bioGUNE) , 48160 Derio , Spain
| | - Jesús Jiménez-Barbero
- Center for Cooperative Research in Biosciences (CIC-bioGUNE) , 48160 Derio , Spain.,Basque Foundation for Science, Ikerbasque , 48013 Bilbo , Spain
| | - Ana M Gómez
- Instituto de Química Orgánica (IQOG-CSIC) , Juan de la Cierva 3 , 28006 Madrid , Spain
| | - Juan Luis Asensio
- Instituto de Química Orgánica (IQOG-CSIC) , Juan de la Cierva 3 , 28006 Madrid , Spain
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23
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van der Vorm S, Hansen T, van Rijssel ER, Dekkers R, Madern JM, Overkleeft HS, Filippov DV, van der Marel GA, Codée JDC. Furanosyl Oxocarbenium Ion Conformational Energy Landscape Maps as a Tool to Study the Glycosylation Stereoselectivity of 2-Azidofuranoses, 2-Fluorofuranoses and Methyl Furanosyl Uronates. Chemistry 2019; 25:7149-7157. [PMID: 30882938 PMCID: PMC6563709 DOI: 10.1002/chem.201900651] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 03/12/2019] [Indexed: 12/16/2022]
Abstract
The 3D shape of glycosyl oxocarbenium ions determines their stability and reactivity and the stereochemical course of SN 1 reactions taking place on these reactive intermediates is dictated by the conformation of these species. The nature and configuration of functional groups on the carbohydrate ring affect the stability of glycosyl oxocarbenium ions and control the overall shape of the cations. We herein map the stereoelectronic substituent effects of the C2-azide, C2-fluoride and C4-carboxylic acid ester on the stability and reactivity of the complete suite of diastereoisomeric furanoses by using a combined computational and experimental approach. Surprisingly, all furanosyl donors studied react in a highly stereoselective manner to provide the 1,2-cis products, except for the reactions in the xylose series. The 1,2-cis selectivity for the ribo-, arabino- and lyxo-configured furanosides can be traced back to the lowest-energy 3 E or E3 conformers of the intermediate oxocarbenium ions. The lack of selectivity for the xylosyl donors is related to the occurrence of oxocarbenium ions adopting other conformations.
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24
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Step-economy synthesis of β-steryl sialosides using a sialyl iodide donor. J Antibiot (Tokyo) 2019; 72:449-460. [PMID: 30886347 DOI: 10.1038/s41429-019-0165-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/12/2019] [Accepted: 02/15/2019] [Indexed: 11/08/2022]
Abstract
Steryl glycosides are prevalent in nature and have unique biological activities dictated by sterol structure, sugar composition, and the stereochemical attachment of the aglycone. A single configurational switch can have profound biological consequences meriting the systematic study of structure and function relationships. Steryl congeners of N-acetyl neuraminic acid (NANA) impact neurobiological processes and may also mediate host/microbe interactions. In order to study these processes, a platform for the synthesis of β-steryl sialosides has been established. Promoter-free glycosidations using a novel α-linked sialyl iodide donor efficiently provide unique amphiphilic sialoglycoconjugates for examining bioactivities in various systems.
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25
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Dhakal B, Crich D. Synthesis and Stereocontrolled Equatorially Selective Glycosylation Reactions of a Pseudaminic Acid Donor: Importance of the Side-Chain Conformation and Regioselective Reduction of Azide Protecting Groups. J Am Chem Soc 2018; 140:15008-15015. [PMID: 30351022 DOI: 10.1021/jacs.8b09654] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Pseudaminic acid is an amino deoxy sialic acid whose glycosides are essential components of many pathogenic Gram-negative bacterial cell walls including those from Pseudomonas aeruginosa, Vibrio cholerae, Campylobacter jejuni, Campylobacter coli, Vibrio vulnificus, and Pseudoalteromonas distincta. The study of pseudaminic acid glycosides is however hampered by poor availability from nature and the paucity of good synthetic methods and limited to no understanding of the factors controlling stereoselectivity. Conformational analysis of the side chains of various stereoisomeric sialic acids suggested that the side chain of pseudaminic acid would take up the most electron-withdrawing trans, gauche-conformation, as opposed to the gauche, gauche conformation of N-acetyl neuraminic acid and the gauche, trans-conformtion of 7- epi N-acetyl neuraminic acid, leading to the prediction of high equatorial selectivity. This prediction is borne out by the synthesis of a suitably protected pseudaminic acid donor from N-acetyl neuraminic acid in 20 steps and 5% overall yield and by the exquisite equatorial selectivity it displays in coupling reactions with typical glycosyl acceptors. The selectivity of the glycosylation reactions is further buttressed by the development and implementation of conditions for the regioselective release of the two amines from the corresponding azides, such as required for the preparation of the lipopolysaccharides. These findings open the way to the synthesis and study of pseudaminic acid-based bacterial lipopolysaccharides and, importantly in the broader context of glycosylation reactions in general, underline the significant role played by side-chain conformation in the control of reactivity and selectivity.
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Affiliation(s)
- Bibek Dhakal
- Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , Michigan 48202 , United States
| | - David Crich
- Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , Michigan 48202 , United States
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26
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Adero PO, Amarasekara H, Wen P, Bohé L, Crich D. The Experimental Evidence in Support of Glycosylation Mechanisms at the S N1-S N2 Interface. Chem Rev 2018; 118:8242-8284. [PMID: 29846062 PMCID: PMC6135681 DOI: 10.1021/acs.chemrev.8b00083] [Citation(s) in RCA: 213] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A critical review of the state-of-the-art evidence in support of the mechanisms of glycosylation reactions is provided. Factors affecting the stability of putative oxocarbenium ions as intermediates at the SN1 end of the mechanistic continuum are first surveyed before the evidence, spectroscopic and indirect, for the existence of such species on the time scale of glycosylation reactions is presented. Current models for diastereoselectivity in nucleophilic attack on oxocarbenium ions are then described. Evidence in support of the intermediacy of activated covalent glycosyl donors is reviewed, before the influences of the structure of the nucleophile, of the solvent, of temperature, and of donor-acceptor hydrogen bonding on the mechanism of glycosylation reactions are surveyed. Studies on the kinetics of glycosylation reactions and the use of kinetic isotope effects for the determination of transition-state structure are presented, before computational models are finally surveyed. The review concludes with a critical appraisal of the state of the art.
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Affiliation(s)
- Philip Ouma Adero
- Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , Michigan 48202 , United States
| | - Harsha Amarasekara
- Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , Michigan 48202 , United States
| | - Peng Wen
- Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , Michigan 48202 , United States
| | - Luis Bohé
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301 , Université Paris-Sud Université Paris-Saclay , 1 avenue de la Terrasse , 91198 Gif-sur-Yvette , France
| | - David Crich
- Department of Chemistry , Wayne State University , 5101 Cass Avenue , Detroit , Michigan 48202 , United States
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27
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Mestre J, Collado D, Benito-Alifonso D, Rodríguez MA, Matheu MI, Díaz Y, Castillón S, Boutureira O. Highly reactive 2-deoxy-2-iodo-d- allo and d- gulo pyranosyl sulfoxide donors ensure β-stereoselective glycosylations with steroidal aglycones. RSC Adv 2018; 8:30076-30079. [PMID: 35546863 PMCID: PMC9085402 DOI: 10.1039/c8ra06619a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 08/11/2018] [Indexed: 12/31/2022] Open
Abstract
The preparation of well-defined d-xylo and d-ribo glycosides represents a synthetic challenge due to the limited configurational availability of starting materials and the laborious synthesis of homogeneous 2-deoxy-β-glycosidic linkages, in particular that of the sugar-steroid motif, which represents the “stereoselective determining step” of the overall synthesis. Herein we describe the use of 2-deoxy-2-iodo-glycopyranosyl sulfoxides accessible from widely available d-xylose and d-ribose monosaccharides as privileged glycosyl donors that permit activation at very low temperature. This ensures a precise kinetic control for a complete 1,2-trans stereoselective glycosylation of particularly challenging steroidal aglycones. Highly stereoselective synthesis of challenging steroidal 2-deoxy-β-glycosides with d-xylo and d-ribo configurations enabled by low temperature activation of 2-deoxy-2-iodoglycopyranosyl sulfoxides.![]()
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Affiliation(s)
- Jordi Mestre
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - David Collado
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - David Benito-Alifonso
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - Miguel A Rodríguez
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - M Isabel Matheu
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - Yolanda Díaz
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - Sergio Castillón
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
| | - Omar Boutureira
- Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili C/Marcel·lí Domingo 1 43007 Tarragona Spain
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28
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Buttar S, Caine J, Goné E, Harris R, Gillman J, Atienza R, Gupta R, Sogi KM, Jain L, Abascal NC, Levine Y, Repka LM, Rojas CM. Glycal Metallanitrenes for 2-Amino Sugar Synthesis: Amidoglycosylation of Gulal-, Allal-, Glucal-, and Galactal 3-Carbamates. J Org Chem 2018; 83:8054-8080. [PMID: 29979042 PMCID: PMC6662188 DOI: 10.1021/acs.joc.8b00893] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The rhodium(II)-catalyzed oxidative cyclization of glycal 3-carbamates with in situ incorporation of an alcohol nucleophile at the anomeric position provides access to a range of 2-amino sugars having 1,2-trans-2,3-cis stereochemistry, a structural motif present in compounds of medicinal and biological significance such as the streptothricin group of antibiotics and the Chitinase inhibitor allosamidin. All of the diastereomeric d-glycal 3-carbamates have been investigated, revealing significant differences in anomeric stereoselectivity depending on substrate stereochemistry and protecting groups. In addition, some substrates were prone to forming C3-oxidized dihydropyranone byproducts under the reaction conditions. Allal- and gulal 3-carbamates provided uniformly high stereo- and chemoselectivity, while for glucal substrates, acyclic, electron-withdrawing protecting groups at the 4 O and 6 O positions were required. Galactal 3-carbamates have been the most challenging substrates; formation of their amidoglycosylation products is most effective with an electron-withdrawing 6 O-Ts substituent and a sterically demanding 4 O-TBS group. These results suggest a mechanism whereby conformational and electronic factors determine the partitioning of an intermediate acyl nitrenoid between alkene addition, leading to amidoglycosylation, and C3-H insertion, providing the dihydropyranone byproduct. Along the amidoglycosylation pathway, high anomeric selectivity results when a glycosyl aziridine intermediate is favored over an aziridine-opened oxocarbenium donor.
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Affiliation(s)
- Simran Buttar
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Julia Caine
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Evelyne Goné
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Reneé Harris
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Jennifer Gillman
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Roxanne Atienza
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Ritu Gupta
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Kimberly M. Sogi
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Lauren Jain
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Nadia C. Abascal
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Yetta Levine
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Lindsay M. Repka
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
| | - Christian M. Rojas
- Department of Chemistry, Barnard College, 3009 Broadway, New York, New York 10027, United States
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29
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Zeng J, Liu Y, Chen W, Zhao X, Meng L, Wan Q. Glycosyl Sulfoxides in Glycosylation Reactions. Top Curr Chem (Cham) 2018; 376:27. [DOI: 10.1007/s41061-018-0205-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/31/2018] [Indexed: 01/01/2023]
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30
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Franconetti A, Jiménez-Barbero J, Cabrera-Escribano F. The Stabilization of Glycosyl Cations Through Cooperative Noncovalent Interactions: A Theoretical Perspective. Chemphyschem 2018; 19:659-665. [DOI: 10.1002/cphc.201700988] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 10/25/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Antonio Franconetti
- Department of Organic Chemistry; Faculty of Chemistry; University of Seville; C/ Profesor García González 1 41012 Sevilla Spain
| | - Jesús Jiménez-Barbero
- Molecular Recognition and Host-Pathogen Interactions; CIC bioGUNE; Bizkaia Technology Park, Building 801 A 48170 Derio Spain
- Basque Foundation for Science; Maria Diaz de Haro 13 48009 Bilbao Spain
- Department of Organic Chemistry II; Faculty of Science and Technology; University of the BasqueCountry; 48940 Leioa Bizkaia Spain
| | - Francisca Cabrera-Escribano
- Department of Organic Chemistry; Faculty of Chemistry; University of Seville; C/ Profesor García González 1 41012 Sevilla Spain
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31
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Parent JF, Deslongchamps P. Bent bonds (τ) and the antiperiplanar hypothesis, and the reactivity at the anomeric center in pyranosides. Org Biomol Chem 2018; 14:11183-11198. [PMID: 27834970 DOI: 10.1039/c6ob02263d] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The stereoselectivity of nucleophilic addition on oxocarbenium ions derived from the bicyclic pyranoside model with or without a C2-OR group can be understood through the use of the bent-bond and the antiperiplanar hypothesis in conjunction with the concept of hyperconjugation as an alternative interpretive model of structure and reactivity.
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Affiliation(s)
- Jean-François Parent
- Département de chimie, Faculté des sciences et de génie, Université Laval, Pavillon Alexandre-Vachon, 1045 avenue de la médecine, Québec, Québec G1V 0A6, Canada.
| | - Pierre Deslongchamps
- Département de chimie, Faculté des sciences et de génie, Université Laval, Pavillon Alexandre-Vachon, 1045 avenue de la médecine, Québec, Québec G1V 0A6, Canada.
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32
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Amarasekara H, Dharuman S, Kato T, Crich D. Synthesis of Conformationally-Locked cis- and trans-Bicyclo[4.4.0] Mono-, Di-, and Trioxadecane Modifications of Galacto- and Glucopyranose; Experimental Limiting 3J H,H Coupling Constants for the Estimation of Carbohydrate Side Chain Populations and Beyond. J Org Chem 2018; 83:881-897. [PMID: 29241001 PMCID: PMC5775050 DOI: 10.1021/acs.joc.7b02891] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hexopyranose side chains populate three staggered conformations, whose proportions can be determined from the three sets of ideal limiting 3JH5,H6R and 3JH5,H6S coupling constants in combination with the time-averaged experimental coupling constants. Literature values for the limiting coupling constants, obtained by the study of model compounds, the use of the Haasnoot-Altona and related equations, or quantum mechanical computations, can result in computed negative populations of one of the three ideal conformations. Such values arise from errors in the limiting coupling constants and/or from the population of nonideal conformers. We describe the synthesis and analysis of a series of cis- and trans-fused mono-, di-, and trioxabicyclo[4.4.0]octane-like compounds. Correction factors for the application of data from internal models (-CH(OR)-CH(OR)-) to terminal systems (-CH(OR)-CH2(OR)) are deduced from comparison of further models, and applied where necessary. Limiting coupling constants so-derived are applied to the side chain conformations of three model hexopyranosides, resulting in calculated conformer populations without negative values. Although, developed primarily for hexopyranose side chains, the limiting coupling constants are suitable, with the correction factors presented, for application to the side chains of higher carbon sugars and to conformation analysis of acyclic diols and their derivatives in a more general sense.
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Affiliation(s)
- Harsha Amarasekara
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - Suresh Dharuman
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - Takayuki Kato
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
| | - David Crich
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
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33
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Exploring cation-π interaction in half sandwiches and sandwiches with X X triple bonds (X C, Si and Ge): A DFT study. COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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34
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van der
Vorm S, Overkleeft HS, van der Marel GA, Codée JDC. Stereoselectivity of Conformationally Restricted Glucosazide Donors. J Org Chem 2017; 82:4793-4811. [PMID: 28401764 PMCID: PMC5423080 DOI: 10.1021/acs.joc.7b00470] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Indexed: 01/08/2023]
Abstract
Glycosylations of 4,6-tethered glucosazide donors with a panel of model acceptors revealed the effect of acceptor nucleophilicity on the stereoselectivity of these donors. The differences in reactivity among the donors were evaluated in competitive glycosylation reactions, and their relative reactivities were found to be reflected in the stereoselectivity in glycosylations with a set of fluorinated alcohols as well as carbohydrate acceptors. We found that the 2-azido-2-deoxy moiety is more β-directing than its C-2-O-benzyl counterpart, as a consequence of increased destabilization of anomeric charge development by the electron-withdrawing azide. Additional disarming groups further decreased the α-selectivity of the studied donors, whereas substitution of the 4,6-benzylidene acetal with a 4,6-di-tert-butyl silylidene led to a slight increase in α-selectivity. The C-2-dinitropyridone group was also explored as an alternative for the nonparticipating azide group, but this protecting group significantly increased β-selectivity. All studied donors exhibited the same acceptor-dependent selectivity trend, and good α-selectivity could be obtained with the weakest acceptors and most reactive donors.
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Affiliation(s)
- Stefan van der
Vorm
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Herman S. Overkleeft
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | | | - Jeroen D. C. Codée
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
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35
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van Rijssel ER, Janssen APA, Males A, Davies GJ, van der Marel GA, Overkleeft HS, Codée JDC. Conformational Behaviour of Azasugars Based on Mannuronic Acid. Chembiochem 2017; 18:1297-1304. [DOI: 10.1002/cbic.201700080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Erwin R. van Rijssel
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Antonius P. A. Janssen
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Alexandra Males
- York Structural Biology Laboratory; Department of Chemistry; The University of York; York YO10 5DD UK
| | - Gideon J. Davies
- York Structural Biology Laboratory; Department of Chemistry; The University of York; York YO10 5DD UK
| | | | - Herman S. Overkleeft
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Jeroen D. C. Codée
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
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36
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Hagen B, Ali S, Overkleeft HS, van der Marel GA, Codée JDC. Mapping the Reactivity and Selectivity of 2-Azidofucosyl Donors for the Assembly of N-Acetylfucosamine-Containing Bacterial Oligosaccharides. J Org Chem 2017; 82:848-868. [PMID: 28051314 PMCID: PMC5332126 DOI: 10.1021/acs.joc.6b02593] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The synthesis of complex oligosaccharides is often hindered by a lack of knowledge on the reactivity and selectivity of their constituent building blocks. We investigated the reactivity and selectivity of 2-azidofucosyl (FucN3) donors, valuable synthons in the synthesis of 2-acetamido-2-deoxyfucose (FucNAc) containing oligosaccharides. Six FucN3 donors, bearing benzyl, benzoyl, or tert-butyldimethylsilyl protecting groups at the C3-O and C4-O positions, were synthesized, and their reactivity was assessed in a series of glycosylations using acceptors of varying nucleophilicity and size. It was found that more reactive nucleophiles and electron-withdrawing benzoyl groups on the donor favor the formation of β-glycosides, while poorly reactive nucleophiles and electron-donating protecting groups on the donor favor α-glycosidic bond formation. Low-temperature NMR activation studies of Bn- and Bz-protected donors revealed the formation of covalent FucN3 triflates and oxosulfonium triflates. From these results, a mechanistic explanation is offered in which more reactive acceptors preferentially react via an SN2-like pathway, while less reactive acceptors react via an SN1-like pathway. The knowledge obtained in this reactivity study was then applied in the construction of α-FucN3 linkages relevant to bacterial saccharides. Finally, a modular synthesis of the Staphylococcus aureus type 5 capsular polysaccharide repeating unit, a trisaccharide consisting of two FucNAc units, is described.
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Affiliation(s)
- Bas Hagen
- Leiden Institute of Chemistry, Universiteit Leiden , Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Sara Ali
- Leiden Institute of Chemistry, Universiteit Leiden , Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Herman S Overkleeft
- Leiden Institute of Chemistry, Universiteit Leiden , Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Gijsbert A van der Marel
- Leiden Institute of Chemistry, Universiteit Leiden , Einsteinweg 55, 2333CC Leiden, The Netherlands
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Universiteit Leiden , Einsteinweg 55, 2333CC Leiden, The Netherlands
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37
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Hernández D, Boto A, Guzmán D, Alvarez E. Metal-free, direct conversion of α-amino acids into α-keto γ-amino esters for the synthesis of α,γ-peptides. Org Biomol Chem 2017; 15:7736-7742. [DOI: 10.1039/c7ob02033c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
An efficient, metal-free synthesis of unusual α-keto γ-amino esters from α-amino acids is achieved by a radical scission–oxidation–addition of silyloxy acrylates procedure, where no purification of the reaction intermediates is needed. The process allows the synthesis of α,γ-peptides.
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Affiliation(s)
- D. Hernández
- Instituto de Productos Naturales y Agrobiología del CSIC
- 38206-La Laguna
- Spain
| | - A. Boto
- Instituto de Productos Naturales y Agrobiología del CSIC
- 38206-La Laguna
- Spain
| | - D. Guzmán
- Instituto de Productos Naturales y Agrobiología del CSIC
- 38206-La Laguna
- Spain
| | - E. Alvarez
- Instituto de Investigaciones Químicas (CSIC-USe)
- Isla de la Cartuja
- 41092-Sevilla
- Spain
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38
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Dhakal B, Buda S, Crich D. Stereoselective Synthesis of 5-epi-α-Sialosides Related to the Pseudaminic Acid Glycosides. Reassessment of the Stereoselectivity of the 5-Azido-5-deacetamidosialyl Thioglycosides and Use of Triflate as Nucleophile in the Zbiral Deamination of Sialic Acids. J Org Chem 2016; 81:10617-10630. [PMID: 27806203 PMCID: PMC5148678 DOI: 10.1021/acs.joc.6b02221] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
With a view to the eventual synthesis of glycosyl donors for the stereocontrolled synthesis of pseudaminic acid glycosides, the stereocontrolled synthesis of a d-glycero-d-gulo sialic acid adamantanylthioglycoside carrying an axial azide at the 5-position is described. The synthesis employs levulinic acid as nucleophile in the oxidative deamination of an N-acetylneuraminic acid thioglycoside leading to the formation of a 3-deoxy-d-glycero-d-galacto-2-nonulosonic acid (KDN) derivative selectively protected as 5-O-levulinate. Replacement of the levulinate by triflate enables introduction of the axial azide and hence formation of the glycosyl donor. A shorter synthesis uses trifluoromethanesulfonate as nucleophile in the oxidative deamination step when the 5-O-triflyl KDN derivative is obtained directly. Glycosylation reactions conducted with the 5-azido-d-glycero-d-gulo-configured sialyl adamantanylthioglycoside at -78 °C are selective for the formation of the equatorial glycosides, suggesting that the synthesis of equatorial pseudaminic acid glycosides will be possible as suitable donors become available. A comparable N-acetylneuraminic acid adamantanylthioglycoside carrying an equatorial azide at the 5-position was also found to be selective for equatorial glycoside formation under the same conditions, suggesting that reinvestigation of other azide-protected NeuAc donors is merited. Glycosylation stereoselectivity in the d-glycero-d-gulo series is discussed in terms of the side-chain conformation of the donor.
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Affiliation(s)
- Bibek Dhakal
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | - Szymon Buda
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | - David Crich
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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39
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Deka BC, Purkayastha SK, Bhattacharyya PK. Formation of thiophene sandwiches through cation–π interaction: A DFT study. COMPUT THEOR CHEM 2016. [DOI: 10.1016/j.comptc.2016.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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40
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Imamura A, Matsuzawa N, Sakai S, Udagawa T, Nakashima S, Ando H, Ishida H, Kiso M. The Origin of High Stereoselectivity in Di-tert-butylsilylene-Directed α-Galactosylation. J Org Chem 2016; 81:9086-9104. [DOI: 10.1021/acs.joc.6b01685] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Akihiro Imamura
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Naomi Matsuzawa
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Shizuo Sakai
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Taro Udagawa
- Department
of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Shinya Nakashima
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Hiromune Ando
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Institute
for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida
Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hideharu Ishida
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Makoto Kiso
- Department
of Applied Bio-organic Chemistry, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
- Institute
for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida
Ushinomiya-cho, Sakyo-ku, Kyoto 606-8501, Japan
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41
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Hernández-Torres G, Mateo J, Colobert F, Urbano A, Carreño MC. Synthesis of Medium-Sized 2,ω-cis-Disubstituted Cyclic Ethers by Reductive Cyclization of Hydroxy Ketones. ChemistrySelect 2016. [DOI: 10.1002/slct.201601161] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gloria Hernández-Torres
- Departamento de Química Orgánica (Módulo 01), Fac. Ciencias; Universidad Autónoma de Madrid; c/ Francisco Tomás y Valiente 7, Cantoblanco 28049- Madrid Spain
| | - Julio Mateo
- Departamento de Química Orgánica (Módulo 01), Fac. Ciencias; Universidad Autónoma de Madrid; c/ Francisco Tomás y Valiente 7, Cantoblanco 28049- Madrid Spain
| | - FranÇoise Colobert
- Laboratoire de Synthèse et Catalyse Asymétrique; Université de Strasbourg (ECPM), UMR CNRS 7509; 25 rue Becquerel 67087 Strasbourg Cedex 02 France
| | - Antonio Urbano
- Departamento de Química Orgánica (Módulo 01), Fac. Ciencias; Universidad Autónoma de Madrid; c/ Francisco Tomás y Valiente 7, Cantoblanco 28049- Madrid Spain
| | - M. Carmen Carreño
- Departamento de Química Orgánica (Módulo 01), Fac. Ciencias; Universidad Autónoma de Madrid; c/ Francisco Tomás y Valiente 7, Cantoblanco 28049- Madrid Spain
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42
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Bag SS, Talukdar S, Anjali S. Regioselective and stereoselective route to N2-β-tetrazolyl unnatural nucleosides via SN2 reaction at the anomeric center of Hoffer’s chlorosugar. Bioorg Med Chem Lett 2016; 26:2044-50. [DOI: 10.1016/j.bmcl.2016.02.078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/17/2016] [Accepted: 02/26/2016] [Indexed: 10/22/2022]
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43
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Dharuman S, Crich D. Determination of the Influence of Side-Chain Conformation on Glycosylation Selectivity using Conformationally Restricted Donors. Chemistry 2016; 22:4535-42. [PMID: 26880055 PMCID: PMC4792696 DOI: 10.1002/chem.201505019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Indexed: 01/28/2023]
Abstract
The synthesis of a series of conformationally locked mannopyranosyl thioglycosides in which the C6-O6 bond adopts either the gauche,gauche, gauche,trans, or trans,gauche conformation is described, and their influence on glycosylation stereoselectivity investigated. Two 4,6-O-benzylidene-protected mannosyl thioglycosides carrying axial or equatorial methyl groups at the 6-position were also synthesized and the selectivity of their glycosylation reactions studied to enable a distinction to be made between steric and stereoelectronic effects. The presence of an axial methoxy group at C6 in the bicyclic donor results in a decreased preference for formation of the β-mannoside, whereas an axial methyl group has little effect on selectivity. The result is rationalized in terms of through-space stabilization of a transient intermediate oxocarbenium ion by the axial methoxy group resulting in a higher degree of SN 1-like character in the glycosylation reaction. Comparisons are made with literature examples and exceptions are discussed in terms of pervading steric effects layered on top of the basic stereoelectronic effect.
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Affiliation(s)
- Suresh Dharuman
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA
| | - David Crich
- Department of Chemistry, Wayne State University, Detroit, MI, 48202, USA.
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44
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45
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Olsen JI, Kowalska K, Pedersen CM, Bols M. Super arming of a glycosyl donor using a molecular lever. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2015.11.052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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Khomutnyk YY, Argüelles AJ, Winschel GA, Sun Z, Zimmerman PM, Nagorny P. Studies of the Mechanism and Origins of Enantioselectivity for the Chiral Phosphoric Acid-Catalyzed Stereoselective Spiroketalization Reactions. J Am Chem Soc 2015; 138:444-56. [DOI: 10.1021/jacs.5b12528] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Yaroslav Ya. Khomutnyk
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
| | - Alonso J. Argüelles
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
| | - Grace A. Winschel
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
| | - Zhankui Sun
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
| | - Paul M. Zimmerman
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
| | - Pavel Nagorny
- Department of Chemistry, University of Michigan, 930 North University
Avenue, Ann Arbor, Michigan 48109, United States
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47
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Wen P, Crich D. Absence of Stereodirecting Participation by 2-O-Alkoxycarbonylmethyl Ethers in 4,6-O-Benzylidene-Directed Mannosylation. J Org Chem 2015; 80:12300-10. [PMID: 26565923 PMCID: PMC4684826 DOI: 10.1021/acs.joc.5b02203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The preparation of a series of mannopyranosyl donors carrying 2-O-(2-oxoalkyl) ethers and their use in glycosylation reactions are described. The formation of cyclic products with the simple 2-O-phenacyl ether and with the 2-O-(t-butoxycarbonylmethyl) ether establishes the stereoelectronic feasibility of participation in such systems. The high β-selectivities observed with the bis-trifluoromethyl phenacyl ether indicate that participation can be suppressed through the introduction of electron-withdrawing substituents. The high β-selectivities and absence of cyclic products observed with the 2-O-(methoxycarbonylmethyl) ether exclude the effective participation of esters through six-membered cyclic intermediates in this series. The results are discussed in terms of the conformation of cyclic dioxenium ions (E,E-, E,Z-, or Z,Z-) and in the context of "neighboring group" participation by nonvicinal esters in glycosylation. Methods for the deprotection of the 2-O-phenacyl and 2-O-(methoxycarbonylmethyl) ethers are described.
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Affiliation(s)
- Peng Wen
- Department of Chemistry, Wayne State University, Detroit, MI 48202,
USA
| | - David Crich
- Department of Chemistry, Wayne State University, Detroit, MI 48202,
USA
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48
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Satoh H, Hansen HS, Manabe S, van Gunsteren WF, Hünenberger PH. Theoretical Investigation of Solvent Effects on Glycosylation Reactions: Stereoselectivity Controlled by Preferential Conformations of the Intermediate Oxacarbenium-Counterion Complex. J Chem Theory Comput 2015; 6:1783-97. [PMID: 26615839 DOI: 10.1021/ct1001347] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mechanism of solvent effects on the stereoselectivity of glycosylation reactions is investigated using quantum-mechanical (QM) calculations and molecular dynamics (MD) simulations, considering a methyl-protected glucopyranoside triflate as a glycosyl donor equivalent and the solvents acetonitrile, ether, dioxane, or toluene, as well as gas-phase conditions (vacuum). The QM calculations on oxacarbenium-solvent complexes do not provide support to the usual solvent-coordination hypothesis, suggesting that an experimentally observed β-selectivity (α-selectivity) is caused by the preferential coordination of a solvent molecule to the reactive cation on the α-side (β-side) of the anomeric carbon. Instead, explicit-solvent MD simulations of the oxacarbenium-counterion (triflate ion) complex (along with corresponding QM calculations) are compatible with an alternative mechanism, termed here the conformer and counterion distribution hypothesis. This new hypothesis suggests that the stereoselectivity is dictated by two interrelated conformational properties of the reactive complex, namely, (1) the conformational preferences of the oxacarbenium pyranose ring, modulating the steric crowding and exposure of the anomeric carbon toward the α or β face, and (2) the preferential coordination of the counterion to the oxacarbenium cation on one side of the anomeric carbon, hindering a nucleophilic attack from this side. For example, in acetonitrile, the calculations suggest a dominant B2,5 ring conformation of the cation with preferential coordination of the counterion on the α side, both factors leading to the experimentally observed β selectivity. Conversely, in dioxane, they suggest a dominant (4)H3 ring conformation with preferential counterion coordination on the β side, both factors leading to the experimentally observed α selectivity.
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Affiliation(s)
- Hiroko Satoh
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology (ETH), CH-8093 Zürich, Switzerland, National Institute of Informatics, Tokyo 101-8430, Japan, and RIKEN Advanced Science Institute, Saitama 351-0198, Japan
| | - Halvor S Hansen
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology (ETH), CH-8093 Zürich, Switzerland, National Institute of Informatics, Tokyo 101-8430, Japan, and RIKEN Advanced Science Institute, Saitama 351-0198, Japan
| | - Shino Manabe
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology (ETH), CH-8093 Zürich, Switzerland, National Institute of Informatics, Tokyo 101-8430, Japan, and RIKEN Advanced Science Institute, Saitama 351-0198, Japan
| | - Wilfred F van Gunsteren
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology (ETH), CH-8093 Zürich, Switzerland, National Institute of Informatics, Tokyo 101-8430, Japan, and RIKEN Advanced Science Institute, Saitama 351-0198, Japan
| | - Philippe H Hünenberger
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology (ETH), CH-8093 Zürich, Switzerland, National Institute of Informatics, Tokyo 101-8430, Japan, and RIKEN Advanced Science Institute, Saitama 351-0198, Japan
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49
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Adero PO, Furukawa T, Huang M, Mukherjee D, Retailleau P, Bohé L, Crich D. Cation Clock Reactions for the Determination of Relative Reaction Kinetics in Glycosylation Reactions: Applications to Gluco- and Mannopyranosyl Sulfoxide and Trichloroacetimidate Type Donors. J Am Chem Soc 2015; 137:10336-45. [PMID: 26207807 PMCID: PMC4545385 DOI: 10.1021/jacs.5b06126] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The development of a cation clock method based on the intramolecular Sakurai reaction for probing the concentration dependence of the nucleophile in glycosylation reactions is described. The method is developed for the sulfoxide and trichloroacetimidate glycosylation protocols. The method reveals that O-glycosylation reactions have stronger concentration dependencies than C-glycosylation reactions consistent with a more associative, S(N)2-like character. For the 4,6-O-benzylidene-directed mannosylation reaction a significant difference in concentration dependence is found for the formation of the β- and α-anomers, suggesting a difference in mechanism and a rationale for the optimization of selectivity regardless of the type of donor employed. In the mannose series the cyclization reaction employed as clock results in the formation of cis and trans-fused oxabicyclo[4,4,0]decanes as products with the latter being strongly indicative of the involvement of a conformationally mobile transient glycosyl oxocarbenium ion. With identical protecting group arrays cyclization in the glucopyranose series is more rapid than in the mannopyranose manifold. The potential application of related clock reactions in other carbenium ion-based branches of organic synthesis is considered.
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Affiliation(s)
- Philip O. Adero
- Department of Chemistry, Wayne State University, 5101 Cass Avenue Detroit, MI 48202, USA
| | - Takayuki Furukawa
- Department of Chemistry, Wayne State University, 5101 Cass Avenue Detroit, MI 48202, USA
| | - Min Huang
- Institut de Chimie des Substances Naturelles, CNRS-ICSN UPR2301, Université Paris-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Debaraj Mukherjee
- Department of Chemistry, Wayne State University, 5101 Cass Avenue Detroit, MI 48202, USA
| | - Pascal Retailleau
- Institut de Chimie des Substances Naturelles, CNRS-ICSN UPR2301, Université Paris-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Luis Bohé
- Institut de Chimie des Substances Naturelles, CNRS-ICSN UPR2301, Université Paris-Sud, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - David Crich
- Department of Chemistry, Wayne State University, 5101 Cass Avenue Detroit, MI 48202, USA
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50
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Szostak R, Aubé J, Szostak M. Determination of Structures and Energetics of Small- and Medium-Sized One-Carbon-Bridged Twisted Amides using ab Initio Molecular Orbital Methods: Implications for Amidic Resonance along the C–N Rotational Pathway. J Org Chem 2015; 80:7905-27. [DOI: 10.1021/acs.joc.5b00881] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Roman Szostak
- Department of Chemistry, Wroclaw University, F. Joliot-Curie 14, Wroclaw 50-383, Poland
| | - Jeffrey Aubé
- Division of Chemical
Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Michal Szostak
- Department of Chemistry, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, United States
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