1
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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.
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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.
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2
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Escopy S, Singh Y, Stine KJ, Demchenko AV. HPLC‐Based Automated Synthesis of Glycans in Solution. Chemistry 2022; 28:e202201180. [DOI: 10.1002/chem.202201180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Samira Escopy
- Department of Chemistry and Biochemistry University of Missouri - St. Louis One University Boulevard St. Louis Missouri 63121 USA
- Department of Chemistry Saint Louis University 3501 Laclede Ave St. Louis Missouri 63103 USA
| | - Yashapal Singh
- Department of Chemistry and Biochemistry University of Missouri - St. Louis One University Boulevard St. Louis Missouri 63121 USA
| | - Keith J. Stine
- Department of Chemistry and Biochemistry University of Missouri - St. Louis One University Boulevard St. Louis Missouri 63121 USA
| | - Alexei V. Demchenko
- Department of Chemistry and Biochemistry University of Missouri - St. Louis One University Boulevard St. Louis Missouri 63121 USA
- Department of Chemistry Saint Louis University 3501 Laclede Ave St. Louis Missouri 63103 USA
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3
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Halder S, Addanki RB, Moktan S, Kancharla PK. Glycosyl o-[1-( p-MeO-Phenyl)vinyl]benzoates (PMPVB) as Easily Accessible, Stable, and Reactive Glycosyl Donors for O-, S-, and C-Glycosylations under Brønsted Acid Catalysis. J Org Chem 2022; 87:7033-7055. [PMID: 35559689 DOI: 10.1021/acs.joc.2c00093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methods suitable for the synthesis of both O- and S-glycosylations are relatively rare because commonly used promoters like halonium sources or gold catalysts are incompatible with thiols as nucleophiles. Here, we present (p-MeO)phenylvinylbenzoates (PMPVB) as easily accessible, stable, and reactive alkene-based glycosyl donors that can be activated with catalytic amounts of a Brønsted acid. This activation protocol not only allows us to synthesize O-glycosides but also can successfully provide S- and C-linked glycosides. The armed and disarmed donors lead to product formation in 5 min, showcasing the high reactivity of the donors. Competitive experiments show that the PMPVB donors are much more reactive than the corresponding PVB donors even under NIS/TMSOTf conditions, whereas PVB donors are not reactive enough to be efficiently activated under Brønsted acid conditions. The potential of the catalytic glycosylation protocol has also been showcased by synthesizing trisaccharides. The Brønsted acid activation of PMPVB donors also allows access to C-glycosides in a stereoselective fashion. The easy accessibility of the donor aglycon on a multigram scale in just two steps makes the PMPVB donors highly attractive alternatives.
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Affiliation(s)
- Suvendu Halder
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Rupa Bai Addanki
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Sangay Moktan
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
| | - Pavan K Kancharla
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, Assam 781039, India
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4
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Escopy S, Singh Y, Demchenko AV. Palladium(II)-assisted activation of thioglycosides. Org Biomol Chem 2021; 19:2044-2054. [PMID: 33599667 DOI: 10.1039/d1ob00004g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Described herein is the first example of glycosidation of thioglycosides in the presence of palladium(ii) bromide. While the activation with PdBr2 alone was proven feasible, higher yields and cleaner reactions were achieved when these glycosylations were performed in the presence of propargyl bromide as an additive. Preliminary mechanistic studies suggest that propargyl bromide assists the reaction by creating an ionizing complex, which accelerates the leaving group departure. A variety of thioglycoside donors in reactions with different glycosyl acceptors were investigated to determine the initial scope of this new reaction. Selective and chemoselective activation of thioglycosides over other leaving groups has also been explored.
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Affiliation(s)
- Samira Escopy
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA.
| | - Yashapal Singh
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA.
| | - Alexei V Demchenko
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA.
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5
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Geringer SA, Singh Y, Hoard DJ, Demchenko AV. A Highly Efficient Glycosidation of Glycosyl Chlorides by Using Cooperative Silver(I) Oxide-Triflic Acid Catalysis. Chemistry 2020; 26:8053-8063. [PMID: 32145116 DOI: 10.1002/chem.201905576] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Indexed: 01/22/2023]
Abstract
Following our discovery that silver(I) oxide-promoted glycosylation with glycosyl bromides can be greatly accelerated in the presence of catalytic TMSOTf or TfOH, we report herein a new discovery that glycosyl chlorides are even more effective glycosyl donors under these reaction conditions. The developed reaction conditions work well with a variety of glycosyl chlorides. Both benzoylated and benzylated chlorides have been successfully glycosidated, and these reaction conditions proved to be effective in coupling substrates containing nitrogen and sulfur atoms. Another convenient feature of this glycosylation is that the progress of the reaction can be monitored visually; its completion can be judged by the disappearance of the characteristic dark color of Ag2 O.
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Affiliation(s)
- Scott A Geringer
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri, 63121, USA
| | - Yashapal Singh
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri, 63121, USA
| | - Daniel J Hoard
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri, 63121, USA
| | - Alexei V Demchenko
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, Missouri, 63121, USA
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6
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Zu Y, Cai C, Sheng J, Cheng L, Feng Y, Zhang S, Zhang Q, Chai Y. n-Pentenyl-Type Glycosides for Catalytic Glycosylation and Their Application in Single-Catalyst One-Pot Oligosaccharide Assemblies. Org Lett 2019; 21:8270-8274. [DOI: 10.1021/acs.orglett.9b03038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yujia Zu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
| | - Chenglin Cai
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
| | - Jingyuan Sheng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
| | - Lili Cheng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
| | - Yingle Feng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
| | - Shengyong Zhang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
| | - Qi Zhang
- School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an, Shaanxi 710119, P. R. China
| | - Yonghai Chai
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Xi’an, Shaanxi 710119, P. R. China
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7
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Kulkarni SS, Wang CC, Sabbavarapu NM, Podilapu AR, Liao PH, Hung SC. "One-Pot" Protection, Glycosylation, and Protection-Glycosylation Strategies of Carbohydrates. Chem Rev 2018; 118:8025-8104. [PMID: 29870239 DOI: 10.1021/acs.chemrev.8b00036] [Citation(s) in RCA: 197] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Carbohydrates, which are ubiquitously distributed throughout the three domains of life, play significant roles in a variety of vital biological processes. Access to unique and homogeneous carbohydrate materials is important to understand their physical properties, biological functions, and disease-related features. It is difficult to isolate carbohydrates in acceptable purity and amounts from natural sources. Therefore, complex saccharides with well-defined structures are often most conviently accessed through chemical syntheses. Two major hurdles, regioselective protection and stereoselective glycosylation, are faced by carbohydrate chemists in synthesizing these highly complicated molecules. Over the past few years, there has been a radical change in tackling these problems and speeding up the synthesis of oligosaccharides. This is largely due to the development of one-pot protection, one-pot glycosylation, and one-pot protection-glycosylation protocols and streamlined approaches to orthogonally protected building blocks, including those from rare sugars, that can be used in glycan coupling. In addition, new automated strategies for oligosaccharide syntheses have been reported not only for program-controlled assembly on solid support but also by the stepwise glycosylation in solution phase. As a result, various sugar molecules with highly complex, large structures could be successfully synthesized. To summarize these recent advances, this review describes the methodologies for one-pot protection and their one-pot glycosylation into the complex glycans and the chronological developments associated with automated syntheses of oligosaccharides.
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Affiliation(s)
- Suvarn S Kulkarni
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India
| | | | | | - Ananda Rao Podilapu
- Department of Chemistry , Indian Institute of Technology Bombay , Mumbai 400076 , India
| | - Pin-Hsuan Liao
- Institute of Chemistry , Academia Sinica , Taipei 115 , Taiwan
| | - Shang-Cheng Hung
- Genomics Research Center , Academia Sinica , Taipei 115 , Taiwan
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8
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El Ashry ESH, Awad LF, Al Moaty MNA, Ghabbour HA, Barakat A. Stereoselective synthesis of novel thioglycosyl heterocycles. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.09.085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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9
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Wang HY, Simmons CJ, Blaszczyk SA, Balzer PG, Luo R, Duan X, Tang W. Isoquinoline-1-Carboxylate as a Traceless Leaving Group for Chelation-Assisted Glycosylation under Mild and Neutral Reaction Conditions. Angew Chem Int Ed Engl 2017; 56:15698-15702. [DOI: 10.1002/anie.201708920] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/15/2017] [Indexed: 01/19/2023]
Affiliation(s)
- Hao-Yuan Wang
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Christopher J. Simmons
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706 USA
| | - Stephanie A. Blaszczyk
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706 USA
| | - Paul G. Balzer
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Renshi Luo
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Xiyan Duan
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Weiping Tang
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706 USA
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10
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Wang HY, Simmons CJ, Blaszczyk SA, Balzer PG, Luo R, Duan X, Tang W. Isoquinoline-1-Carboxylate as a Traceless Leaving Group for Chelation-Assisted Glycosylation under Mild and Neutral Reaction Conditions. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708920] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Hao-Yuan Wang
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Christopher J. Simmons
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706 USA
| | - Stephanie A. Blaszczyk
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706 USA
| | - Paul G. Balzer
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Renshi Luo
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Xiyan Duan
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
| | - Weiping Tang
- Pharmaceutical Sciences Division; School of Pharmacy; University of Wisconsin-Madison; 777 Highland Avenue Madison WI 53705 USA
- Department of Chemistry; University of Wisconsin-Madison; 1101 University Avenue Madison WI 53706 USA
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11
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Hu Y, Yu K, Shi LL, Liu L, Sui JJ, Liu DY, Xiong B, Sun JS. o-(p-Methoxyphenylethynyl)phenyl Glycosides: Versatile New Glycosylation Donors for the Highly Efficient Construction of Glycosidic Linkages. J Am Chem Soc 2017; 139:12736-12744. [DOI: 10.1021/jacs.7b07020] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yang Hu
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - Ke Yu
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - Li-Li Shi
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - Lei Liu
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - Jing-Jing Sui
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - De-Yong Liu
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - Bin Xiong
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
| | - Jian-Song Sun
- The National Research Centre
for Carbohydrate Synthesis, Jiangxi Normal University, 99 Ziyang
Avenue, Nanchang 330022, China
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12
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Hasty SJ, Bandara MD, Rath NP, Demchenko AV. S-Benzimidazolyl (SBiz) Imidates as a Platform for Oligosaccharide Synthesis via Active-Latent, Armed-Disarmed, Selective, and Orthogonal Activations. J Org Chem 2017; 82:1904-1911. [PMID: 28135419 PMCID: PMC5498158 DOI: 10.1021/acs.joc.6b02478] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This article describes the development of S-benzimidazolyl (SBiz) imidates as versatile building blocks for oligosaccharide synthesis. The SBiz imidates have been originally developed as a new platform for active-latent glycosylations. This article expands upon the utility of these compounds. The application to practically all common concepts for the expeditious oligosaccharide synthesis including selective, chemoselective, and orthogonal strategies is demonstrated. The strategy development was made possible thanks to our enhanced understanding of the reaction mechanism and the modes by which SBiz imidates interact with various promoters of glycosylation.
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Affiliation(s)
- Scott J. Hasty
- Department of Chemistry and Biochemistry, University of Missouri—St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States
| | - Mithila D. Bandara
- 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
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13
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Pornsuriyasak P, Jia XG, Kaeothip S, Demchenko AV. Templated Oligosaccharide Synthesis: The Linker Effect on the Stereoselectivity of Glycosylation. Org Lett 2016; 18:2316-9. [PMID: 27115718 DOI: 10.1021/acs.orglett.6b01102] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new method for intramolecular oligosaccharide synthesis that is conceptually related to the general molecular clamp approach is introduced. Exceptional α-selectivity has been achieved in a majority of applications. Unlike other related concepts, this approach is based on the bisphenol A template, which allows one to connect multiple building blocks to perform templated oligosaccharide synthesis with complete stereoselectivity. This principle was demonstrated by the synthesis of an α,α-linked trisaccharide.
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Affiliation(s)
- Papapida Pornsuriyasak
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis , One University Boulevard, St. Louis, Missouri 63121, United States
| | - Xiao G Jia
- Department of Chemistry and Biochemistry, University of Missouri-St. Louis , One University Boulevard, St. Louis, Missouri 63121, United States
| | - Sophon Kaeothip
- 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
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14
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Mukherjee MM, Basu N, Ghosh R. Iron(iii) chloride modulated selective 1,2-trans glycosylation based on glycosyl trichloroacetimidate donors and its application in orthogonal glycosylation. RSC Adv 2016. [DOI: 10.1039/c6ra21859h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
FeCl3 modulated excellent 1,2-trans selective glycosylations based on trichloroacetimidate glycosyl donors even in the presence of apparently silent C-2 protecting group, along with orthogonal glycosylation reactions are reported.
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Affiliation(s)
| | - Nabamita Basu
- Department of Chemistry
- Jadavpur University
- Kolkata 700032
- India
| | - Rina Ghosh
- Department of Chemistry
- Jadavpur University
- Kolkata 700032
- India
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15
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Lindhorst TK. Multivalent glycosystems for nanoscience. Beilstein J Org Chem 2014; 10:2345-7. [PMID: 25383104 PMCID: PMC4222442 DOI: 10.3762/bjoc.10.244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 09/24/2014] [Indexed: 12/15/2022] Open
Affiliation(s)
- Thisbe K Lindhorst
- Otto Diels Institute of Organic Chemistry, Christiana Albertina University of Kiel, Otto-Hahn-Platz 3/4, 24098 Kiel, Germany
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16
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Ranade SC, Demchenko AV. Glycosyl alkoxythioimidates as building blocks for glycosylation: a reactivity study. Carbohydr Res 2014; 403:115-22. [PMID: 25043398 DOI: 10.1016/j.carres.2014.06.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/16/2014] [Accepted: 06/22/2014] [Indexed: 12/13/2022]
Abstract
Structural modifications of the leaving group of S-glycosyl O-methyl phenylcarbamothioates (SNea) involving change of substituents that express different electronic effects led to a better understanding of how the reactivity of these glycosyl donors can be modified by changing the structure of their leaving groups. Mechanistic studies involving the isolation of departed aglycones were indicative of the direct activation of both p-methoxy-SNea and p-nitro-SNea leaving groups via the anomeric sulfur rather than the remote nitrogen atom. The presence of an electron donating substituent (p-methoxy) has a strong effect on the nucleophilicity of the sulfur atom that becomes more susceptible toward the attack of thiophilic reagents, in particular. This key observation allowed to differentiate the reactivity levels of p-methoxy-SNea versus p-nitro-SNea and even unmodified SNea leaving groups. The reactivity difference observed in the series of SNea leaving groups is sufficient to be exploited in expeditious oligosaccharide synthesis via selective activation strategies.
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Affiliation(s)
- Sneha C Ranade
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, St. Louis, MO 63121, USA
| | - Alexei V Demchenko
- Department of Chemistry and Biochemistry, University of Missouri - St. Louis, St. Louis, MO 63121, USA.
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17
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Ranade SC, Demchenko AV. Mechanism of Chemical Glycosylation: Focus on the Mode of Activation and Departure of Anomeric Leaving Groups. J Carbohydr Chem 2013. [DOI: 10.1080/07328303.2012.749264] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Sneha C. Ranade
- a Department of Chemistry and Biochemistry , University of Missouri , St. Louis , MO , 63121 , USA
| | - Alexei V. Demchenko
- a Department of Chemistry and Biochemistry , University of Missouri , St. Louis , MO , 63121 , USA
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