1
|
Demchenko AV, De Meo C. The 4K reaction. Carbohydr Res 2024; 538:109102. [PMID: 38569333 DOI: 10.1016/j.carres.2024.109102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/05/2024]
Abstract
The classical Koenigs-Knorr glycosidation of bromides or chlorides promoted with Ag2O or Ag2CO3 works only with reactive substrates (ideally both donor and acceptor). This reaction was found to be practically ineffective with unreactive donors such as per-O-benzoylated mannosyl bromide. Recently, it was discovered that the addition of catalytic (Lewis) acids to a silver salt-promoted reaction has a dramatic effect on the reaction rate and yield. A tentative mechanism for this cooperatively-catalyzed glycosylation reaction has been proposed, and the improved understanding of the reaction led to more efficient protocols and broader applications to a variety of glycosidic linkages. Since Ag2O-mediated activation was introduced by German chemists Koenigs and Knorr, and "cooperatively catalyzed" is Kooperativ Katalysiert in German, we refer to this new reaction as "the 4K reaction."
Collapse
Affiliation(s)
- Alexei V Demchenko
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave, St. Louis, Missouri, 63103, United States.
| | - Cristina De Meo
- Department of Chemistry, Southern Illinois University Edwardsville, 1 Hairpin Dr., Edwardsville, IL, 62025, United States
| |
Collapse
|
2
|
Mamirgova ZZ, Zinin AI, Chizhov AO, Kononov LO. Synthesis of sialyl halides with various acyl protective groups. Carbohydr Res 2024; 536:109033. [PMID: 38295530 DOI: 10.1016/j.carres.2024.109033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/31/2023] [Accepted: 01/05/2024] [Indexed: 02/02/2024]
Abstract
Glycosyl halides are historically one of the first glycosyl donors used in glycosylation reactions, and interest in glycosylation reactions involving this class of glycosyl donors is currently increasing. New methods for their activation have been proposed and effective syntheses of oligosaccharides with their participation have been developed. At the same time, the possibilities of using these approaches to the synthesis of sialosides are restricted by the limited diversity of known sialyl halides (previously, mainly sialyl chlorides, less often sialyl bromides and sialyl fluorides, with acetyl (Ac) groups at the oxygen atoms and AcNH, Ac2N and N3 groups at C-5 were used). This work describes the synthesis of six new N-acetyl- and N-trifluoroacetyl-sialyl chlorides and bromides with O-chloroacetyl and O-trifluoroacetyl protective groups. Preparation of N,O-trifluoroacetyl protected derivatives was made possible due to development of the synthesis of sialic acid methyl ester pentaol with N-trifluoroacetyl group.
Collapse
Affiliation(s)
- Zarina Z Mamirgova
- N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 47, 119991, Russian Federation
| | - Alexander I Zinin
- N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 47, 119991, Russian Federation
| | - Alexander O Chizhov
- N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 47, 119991, Russian Federation
| | - Leonid O Kononov
- N. D. Zelinsky Institute of Organic Chemistry of the Russian Academy of Sciences, Leninsky Prosp. 47, 119991, Russian Federation.
| |
Collapse
|
3
|
Buntasana S, Padungros P. Glycosylation of n-pentenyl glycosides using bromodiethylsulfonium salt as an activator: interception of the glycosyl intermediate by chloride ion transfer. Org Biomol Chem 2023; 22:126-143. [PMID: 38051124 DOI: 10.1039/d3ob01618h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Utilization of n-pentenyl glycosides (NPGs) in modern carbohydrate synthesis may be hindered by their sluggish activation, which results from reversible halogenation and cyclization processes. Bromodiethylsulfonium bromopentachloroantimonate (BDSB) has been previously shown to be a powerful brominating agent for the cation-π polyene cyclization of less reactive and electron-poor polyenes. This study demonstrates the activation of NPGs using BDSB as a powerful brominating agent. BDSB effectively activates the terminal olefins of NPGs and the reaction proceeds through 5-exo-tet cyclization, offering a rapid and mild approach for glycosylation with a wide range of glycosyl donors, including n-pentenyl mannoside, n-pentenyl galactoside, and n-pentenyl glucoside. The success of this approach derives from the chloride ion transfer from the nonnucleophilic SbCl5Br anion to the glycosyl intermediate, which disrupts the equilibrium and produces a glycosyl chloride intermediate that is smoothly converted to 22 coupling products, with yields ranging from moderate to excellent (49-100%). The β-selective glycosylation is accomplished when employing NPGs equipped with a neighboring participating group. The practicality of the BDSB-activated glycosylation is demonstrated by a gram-scale synthesis. This study showcases BDSB as a potent activator for NPG glycosylation through the interception of a glycosyl intermediate that diminishes the equilibration during halogenation and 5-exo-tet cyclization.
Collapse
Affiliation(s)
- Supanat Buntasana
- Green Chemistry for Fine Chemical Production and Environmental Remediation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
| | - Panuwat Padungros
- Green Chemistry for Fine Chemical Production and Environmental Remediation Research Unit, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok 10330, Thailand.
| |
Collapse
|
4
|
Khanam A, Dubey S, Mandal PK. Mild method for the synthesis of α-glycosyl chlorides: A convenient protocol for quick one-pot glycosylation. Carbohydr Res 2023; 534:108976. [PMID: 37871478 DOI: 10.1016/j.carres.2023.108976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 10/25/2023]
Abstract
A simple and efficient protocol for the preparation of α-glycosyl chlorides within 15-30 min is described which employs a stable, cheap, and commercially available Trichloroisocyanuric acid (TCCA) as non-toxic chlorinating agent along with PPh3. This process involved a wide range of substrate scope and is well-suited with labile hydroxyl protecting groups such as benzyl, acetyl, benzoyl, isopropylidene, benzylidene, and TBDPS (tert-butyldiphenylsilyl) groups. This process is operationally simple, mild conditions and obtained good yields with excellent α selectivity. Moreover, a multi-catalyst one-pot glycosylation can be carried out to transform the glycosyl hemiacetals directly to a various O-glycosides in high overall yields without the need for separation or purification of the α-glycosyl chloride donors.
Collapse
Affiliation(s)
- Ariza Khanam
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow, 226 031, India
| | - Shashiprabha Dubey
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow, 226 031, India
| | - Pintu Kumar Mandal
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, BS-10/1, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow, 226 031, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| |
Collapse
|
5
|
Romerio A, Franco AR, Shadrick M, Shaik MM, Artusa V, Italia A, Lami F, Demchenko AV, Peri F. Overcoming Challenges in Chemical Glycosylation to Achieve Innovative Vaccine Adjuvants Possessing Enhanced TLR4 Activity. ACS OMEGA 2023; 8:36412-36417. [PMID: 37810727 PMCID: PMC10552098 DOI: 10.1021/acsomega.3c05363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/23/2023] [Indexed: 10/10/2023]
Abstract
Lipopolysaccharide (LPS) mimicry leading to toll-like receptor 4 (TLR4) active compounds has been so far based mainly on reproducing the lipid A portion of LPS. Our work led to a series of structurally simplified synthetic TLR4 agonists in preclinical development as vaccine adjuvants called FPs. FPs bind MD2/TLR4 similarly to lipid A, inserting the lipid chains in the MD2 lipophilic cavity. A strategy to improve FPs' target affinity is introducing a monosaccharide unit in C6, mimicking the first sugar of the LPS core. We therefore designed a panel of FP derivatives bearing different monosaccharides in C6. We report here the synthesis and optimization of FPs' C6 glycosylation, which presented unique challenges and limitations. The biological activity of glycosylated FP compounds was preliminarily assessed in vitro in HEK-Blue cells. The new molecules showed a higher potency in stimulating TLR4 activation when compared to the parent molecule while maintaining TLR4 selectivity.
Collapse
Affiliation(s)
- Alessio Romerio
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| | - Ana Rita Franco
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| | - Melanie Shadrick
- Department
of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| | - Mohammed Monsoor Shaik
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| | - Valentina Artusa
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| | - Alice Italia
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| | - Federico Lami
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| | - Alexei V. Demchenko
- Department
of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| | - Francesco Peri
- Department
of Biotechnology and Biosciences, University
of Milano-Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy
| |
Collapse
|
6
|
Gao K, Qin Y, Liu S, Wang L, Xing R, Yu H, Chen X, Li P. A review of the preparation, derivatization and functions of glucosamine and N-acetyl-glucosamine from chitin. CARBOHYDRATE POLYMER TECHNOLOGIES AND APPLICATIONS 2023. [DOI: 10.1016/j.carpta.2023.100296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
|
7
|
Shadrick M, Stine KJ, Demchenko AV. Expanding the scope of stereoselective α-galactosylation using glycosyl chlorides. Bioorg Med Chem 2022; 73:117031. [PMID: 36202065 PMCID: PMC9677435 DOI: 10.1016/j.bmc.2022.117031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/20/2022]
Abstract
Recently, we reported that silver(I) oxide mediated Koenigs-Knorr glycosylation reaction can be dramatically accelerated in the presence of catalytic acid additives. We have also investigated how well this reaction works in application to differentially protected galactosyl bromides. Reported herein is the stereoselective synthesis of α-galactosides with galactosyl chlorides as glycosyl donors. Chlorides are easily accessible, stable, and can be efficiently activated for glycosylation. In this application, the most favorable reactions conditions comprised cooperative Ag2SO4 and Bi(OTf)3 promoter system.
Collapse
Affiliation(s)
- Melanie Shadrick
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave, St. Louis, MO 63103, USA; Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA
| | - Keith J Stine
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA
| | - Alexei V Demchenko
- Department of Chemistry, Saint Louis University, 3501 Laclede Ave, St. Louis, MO 63103, USA; Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA.
| |
Collapse
|
8
|
Jouandon N, Hammoud J, Touron A, Bailly L, Le Foll A, Joosten AYP, Lecourt T. Preparation of propargyl 1,2-orthoesters of carbohydrates: From side reactions in dichloromethane to optimized reaction conditions in acetonitrile. Carbohydr Res 2022; 521:108652. [PMID: 36037648 DOI: 10.1016/j.carres.2022.108652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 08/18/2022] [Accepted: 08/18/2022] [Indexed: 11/02/2022]
Abstract
In this note, supercritical fluid chromatography coupled to high-resolution mass spectrometry (SFC-HRMS) has been used to identify a chloro glycoside formed during the preparation of propargyl 1,2-orthoesters in dichloromethane. Additional studies revealed that 20-40% of this side-product was obtained depending on the source of anhydrous solvent, and that tetrabutylammonium iodide amplifies this side-reaction. Finally, a reliable procedure was developed in acetonitrile to prepare these glycosyl donors from perbenzoylated bromo glycosides in manno, gluco and galacto series in 63-74% yield.
Collapse
Affiliation(s)
- Nicolas Jouandon
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
| | - Jana Hammoud
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
| | - Alexandre Touron
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
| | - Laetitia Bailly
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
| | - Alexandra Le Foll
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
| | - Antoine Y P Joosten
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France
| | - Thomas Lecourt
- Normandie Univ, INSA Rouen, UNIROUEN, CNRS, COBRA UMR 6014, 76000, Rouen, France.
| |
Collapse
|
9
|
Singh Y, Geringer SA, Demchenko AV. Synthesis and Glycosidation of Anomeric Halides: Evolution from Early Studies to Modern Methods of the 21st Century. Chem Rev 2022; 122:11701-11758. [PMID: 35675037 DOI: 10.1021/acs.chemrev.2c00029] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Advances in synthetic carbohydrate chemistry have dramatically improved access to common glycans. However, many novel methods still fail to adequately address challenges associated with chemical glycosylation and glycan synthesis. Since a challenge of glycosylation has remained, scientists have been frequently returning to the traditional glycosyl donors. This review is dedicated to glycosyl halides that have played crucial roles in shaping the field of glycosciences and continue to pave the way toward our understanding of chemical glycosylation.
Collapse
Affiliation(s)
- Yashapal Singh
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Scott A Geringer
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Alexei V Demchenko
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States.,Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States
| |
Collapse
|
10
|
Chooppawa T, Janprasert P, Padungros P. One-Pot Synthesis of Glycosyl Chlorides from Thioglycosides Mediated by Bromodiethylsulfonium Salt as A Mild Oxidant. Synlett 2022. [DOI: 10.1055/a-1852-6889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Conventional synthesis of glycosyl chlorides from thioglycosides relies on the two sequential oxidation and chlorination. A one-pot synthesis of glycosyl chlorides is warranted as an alternative method. Herein, we report the one-pot synthesis of glycosyl chlorides from thioglycoside precursors. The transformation was mediated at low temperature by bromodiethylsulfonium bromopentachloroantimonate (BDSB) as a mild oxidant and n-Bu4NCl as an additive. The armed thioglycosides afforded the corresponding α-glycosyl chlorides in moderate to good yields under the optimized conditions. Low conversions and yields were obtained when the less reactive disarmed thioglycosides were used. Unexpectedly, BDSB-mediated oxidation of thioglycosides without the addition of n-Bu4NCl also afforded the α-glycosyl chlorides in moderate yields. We suggest a mechanism involving the transfer of chloride ions from the non-nucleophilic bromopentachloroantimonate (SbCl5Br) anion to the oxocarbenium ion.
Collapse
Affiliation(s)
- Tianchai Chooppawa
- Chemistry, Chulalongkorn University Faculty of Science, Bangkok, Thailand
| | | | - Panuwat Padungros
- Chemistry, Chulalongkorn University Faculty of Science, Bangkok, Thailand
| |
Collapse
|
11
|
Kasdekar N, Walke G, Deshpande K, Hotha S. Glycosyl Vinylogous Carbonates as Glycosyl Donors by Metal-Free Activation. J Org Chem 2022; 87:5472-5484. [PMID: 35414184 DOI: 10.1021/acs.joc.1c02427] [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
Synthesis of glycoconjugates employs a glycosylation reaction wherein an electrophile and a nucleophile known as a glycosyl donor and an aglycon, respectively, are involved. Glycosyl donors often contain a leaving group at the anomeric carbon that upon reaction with activator(s) results in a highly reactive electrophilic species reported as an oxycarbenium ion contact pair that will then be attacked by the aglycon. Therefore, identification of the correct glycosyl donor and activation protocol is essential for the synthesis of all glycoconjugates. Recently identified [Au]/[Ag]-catalyzed activation of ethynylcyclohexyl glycosyl carbonates is one such versatile method for the synthesis of glycosides, oligosaccharides, and glycoconjugates. In this work, stable glycosyl vinylogous carbonates were identified to undergo glycosidation in the presence of a sub-stoichiometric quantity of TfOH. The reaction is fast and suitable for donors containing both C2-ethers and C2-esters. Donors positioned with C2-ethers resulted in anomeric mixtures with greater selectivity toward 1,2-cis glycosides, whereas those with C2-esters gave 1,2-trans selective glycosides. The versatility of the method is demonstrated by conducting the glycosylation with more than 25 substrates. Furthermore, the utility of the glycosyl vinylogous carbonate donors is demonstrated with the successful synthesis of the branched pentaarabinofuranoside moiety of the Mycobacterium tuberculosis cell wall.
Collapse
Affiliation(s)
- Niteshlal Kasdekar
- Department of Chemistry, Indian Institute of Science Education and Research Pune 411 008, India
| | - Gulab Walke
- Department of Chemistry, Indian Institute of Science Education and Research Pune 411 008, India
| | - Kshitij Deshpande
- Department of Chemistry, Indian Institute of Science Education and Research Pune 411 008, India
| | - Srinivas Hotha
- Department of Chemistry, Indian Institute of Science Education and Research Pune 411 008, India
| |
Collapse
|
12
|
Myachin IV, Mamirgova ZZ, Stepanova EV, Zinin AI, Chizhov AO, Kononov L. Black swan in phase transfer catalysis: influence of mixing mode on the stereoselectivity of glycosylation. European J Org Chem 2022. [DOI: 10.1002/ejoc.202101377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Ilya V. Myachin
- Zelinsky Institute of Organic Chemistry RAS: Institut organiceskoj himii imeni N D Zelinskogo RAN Laboratory of Glycochemistry RUSSIAN FEDERATION
| | - Zarina Z. Mamirgova
- Zelinsky Institute of Organic Chemistry RAS: Institut organiceskoj himii imeni N D Zelinskogo RAN Laboratory of Glycochemistry RUSSIAN FEDERATION
| | - Elena V. Stepanova
- Zelinsky Institute of Organic Chemistry RAS: Institut organiceskoj himii imeni N D Zelinskogo RAN Laboraory of Glycochemistry RUSSIAN FEDERATION
| | - Alexander I. Zinin
- Zelinsky Institute of Organic Chemistry RAS: Institut organiceskoj himii imeni N D Zelinskogo RAN Laboratory of Glycochemistry RUSSIAN FEDERATION
| | - Alexander O. Chizhov
- Zelinsky Institute of Organic Chemistry RAS: Institut organiceskoj himii imeni N D Zelinskogo RAN Laboratory of Glycochemistry RUSSIAN FEDERATION
| | - Leonid Kononov
- N.D. Zelinsky Institute of Organic Chemistry Laboratory of Glycochemistry Leninsky prosp., 47 119991 Moscow RUSSIAN FEDERATION
| |
Collapse
|
13
|
Lin MH, Chang CW, Chiang TY, Dhurandhare VM, Wang CC. Thiocarbonyl as a Switchable Relay-Auxiliary Group in Carbohydrate Synthesis. Org Lett 2021; 23:7313-7318. [PMID: 34269593 DOI: 10.1021/acs.orglett.1c01968] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A multifunctional O-phenyl thiocarbonyl (O(C═S)OPh) group was introduced in glycosylation reactions. This auxiliary group exhibits three features (1) C6-long-range participation effect, (2) relay activation, and (3) switchable promoter-controlled carbonylation, which enables the facile synthesis of both 6-deoxy glucoside and 6-alcohol glucoside. In addition, we successfully quantified the extent of the C6-acyl participation effect and developed its application toward the α-trisaccharide motif.
Collapse
|
14
|
Steber HB, Singh Y, Demchenko AV. Bismuth(iii) triflate as a novel and efficient activator for glycosyl halides. Org Biomol Chem 2021; 19:3220-3233. [PMID: 33885577 PMCID: PMC8112625 DOI: 10.1039/d1ob00093d] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Presented herein is the discovery that bismuth(iii) trifluoromethanesulfonate (Bi(OTf)3) is an effective catalyst for the activation of glycosyl bromides and glycosyl chlorides. The key objective for the development of this methodology is to employ only one promoter in the lowest possible amount and to avoid using any additive/co-catalyst/acid scavenger except molecular sieves. Bi(OTf)3 works well in promoting the glycosidation of differentially protected glucosyl, galactosyl, and mannosyl halides with many classes of glycosyl acceptors. Most reactions complete within 1 h in the presence of only 35% of green and light-stable Bi(OTf)3 catalyst.
Collapse
Affiliation(s)
- Hayley B Steber
- Department of Chemistry and Biochemistry, University of Missouri - St Louis, One University Boulevard, St Louis, Missouri 63121, USA.
| | | | | |
Collapse
|
15
|
Shrestha G, Panza M, Singh Y, Rath NP, Demchenko AV. Indolylthio Glycosides As Effective Building Blocks for Chemical Glycosylation. J Org Chem 2020; 85:15885-15894. [PMID: 32627548 DOI: 10.1021/acs.joc.0c00943] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The S-indolyl (SIn) anomeric moiety was investigated as a new leaving group that can be activated for chemical glycosylation under a variety of conditions including thiophilic and metal-assisted pathways. Understanding of the reaction pathways for the SIn moiety activation was achieved via the extended mechanistic study. Also reported is how the new SIn donors fit into selective activation strategies for oligosaccharide synthesis.
Collapse
Affiliation(s)
- Ganesh Shrestha
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Matteo Panza
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Yashapal Singh
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Nigam P Rath
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Alexei V Demchenko
- Department of Chemistry and Biochemistry, University of Missouri, St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| |
Collapse
|