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Santana AG, Herrera AJ, González CC. Intramolecular Metal-Free C(sp 3)-H Activation Enables a Selective Mono O-Debenzylation of Fully Protected Aminosugars. J Org Chem 2021; 86:16736-16752. [PMID: 34807601 DOI: 10.1021/acs.joc.1c01977] [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
Carbamate-bearing benzylated aminosugars undergo an I2/I(III)-promoted intramolecular hydrogen atom transfer (IHAT) followed by a nucleophilic attack to provide polycyclic structures. Thus, suitably positioned benzyl ethers are surgically oxidized into the corresponding mixed N/O-benzylidene acetals, which can be conveniently deprotected under mild acidic conditions to grant access to selectively O-deprotected aminosugars amenable for further derivatization. The scope of this strategy has been proven with a series of furanosic and pyranosic scaffolds. Preliminary mechanistic studies, including Hammett LFER and KIE analyses, support a reaction pathway with nucleophilic cyclization as the rate-determining step.
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Affiliation(s)
- Andrés G Santana
- Instituto de Productos Naturales y Agrobiología del C.S.I.C., Avenida Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Spain
| | - Antonio J Herrera
- Instituto de Productos Naturales y Agrobiología del C.S.I.C., Avenida Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Spain
| | - Concepción C González
- Instituto de Productos Naturales y Agrobiología del C.S.I.C., Avenida Astrofísico Francisco Sánchez 3, 38206 La Laguna, Tenerife, Spain
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2
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Sridhar PR, Anjaneyulu B, Rao BU. Regioselective Anomeric
O
‐Benzyl Deprotection in Carbohydrates. European J Org Chem 2021. [DOI: 10.1002/ejoc.202101033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Perali Ramu Sridhar
- School of Chemistry University of Hyderabad Hyderabad, Gachibowli 500046 India
| | - Bandi Anjaneyulu
- School of Chemistry University of Hyderabad Hyderabad, Gachibowli 500046 India
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Moriyama K, Nakamura Y, Togo H. Oxidative Debenzylation of N-Benzyl Amides and O-Benzyl Ethers Using Alkali Metal Bromide. Org Lett 2014; 16:3812-5. [DOI: 10.1021/ol501703y] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katsuhiko Moriyama
- Department
of Chemistry, Graduate School of Science, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Yu Nakamura
- Department
of Chemistry, Graduate School of Science, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Hideo Togo
- Department
of Chemistry, Graduate School of Science, Chiba University, 1-33
Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
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4
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Yin ZJ, Wang B, Li YB, Meng XB, Li ZJ. Highly efficient and mild method for regioselective de-O-benzylation of saccharides by Co2(CO)8-Et3SiH-CO reagent system. Org Lett 2010; 12:536-9. [PMID: 20058892 DOI: 10.1021/ol902717y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A highly efficient and mild method for the de-O-benzylation of protected saccharides was developed by transforming terminal benzyl ethers into silyl ethers using Co(2)(CO)(8)-Et(3)SiH under 1 atm of CO. The method was successfully used for the de-O-benzylation of perbenzylated monosaccharides with various anomeric protecting groups, as well as natural disaccharides and trisaccharides such as sucrose, raffinose, and melezitose in good yields (>80%).
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Affiliation(s)
- Zhao-Jun Yin
- The State Key Laboratory of Natural and Biomimetic of Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, P. R. China
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Rawal GK, Rani S, Kumari N, Vankar YD. Regio- and Stereocontrolled Selective Debenzylation and Substitution Reactions of C-2 Formyl Glycals. Application in the Synthesis of Constrained β-Sugar Amino Acids. J Org Chem 2009; 74:5349-55. [DOI: 10.1021/jo9008222] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Girish K. Rawal
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Shikha Rani
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Nitee Kumari
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Yashwant D. Vankar
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
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Abstract
We have investigated the use of sonication for the synthesis of oligomannosides. A convenient sonication-mediated glycosylation protocol that is applicable to traditional glycosylation methods has been developed. This protocol can be applicable for activating glycosyl donors that are known to have low reactivity which enable the synthesis of oligomannosides of particular biological interest with the same efficiency.
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Affiliation(s)
- Christabel T Tanifum
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, Utah 84322-0300, USA
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Fan R, Li W, Pu D, Zhang L. Transition-Metal-Free Intermolecular Amination of sp3 C−H Bonds with Sulfonamides. Org Lett 2009; 11:1425-8. [DOI: 10.1021/ol900090f] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Renhua Fan
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, China
| | - Weixun Li
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, China
| | - Dongming Pu
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, China
| | - Li Zhang
- Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, China
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Boto A, Hernández D, Hernández R, Suárez E. Efficient and selective removal of methoxy protecting groups in carbohydrates. Org Lett 2006; 6:3785-8. [PMID: 15469349 DOI: 10.1021/ol048439+] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The selective removal from carbohydrate substrates of methoxy protecting groups next to hydroxy groups is reported. On treatment with PhI(OAc)(2)-I(2), the methoxy group is transformed into an easily removable acetal. The mild conditions of this methodology are compatible with many functional groups, and good to excellent yields are usually achieved.
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Affiliation(s)
- Alicia Boto
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Fco. Sánchez 3, 38206-La Laguna, Tenerife, Spain.
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9
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Boto A, Hernández D, Hernández R, Suárez E. Selective Cleavage of Methoxy Protecting Groups in Carbohydrates. J Org Chem 2006; 71:1938-48. [PMID: 16496979 DOI: 10.1021/jo052313o] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The selective cleavage of methoxy protecting groups next to hydroxy groups is achieved using a radical hydrogen abstraction reaction as the key step. Under the reaction conditions, the hydroxy group generates an alkoxyl radical that reacts with the sterically accessible adjacent methoxy group, which is transformed into an acetal. In the second step, the acetals are hydrolyzed to give alcohols or diols. A one-pot hydrogen abstraction-hydrolysis procedure was also developed. Good yields were usually achieved, and the mild conditions of this methodology were compatible with different functional groups and sensitive substrates such as carbohydrates.
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Affiliation(s)
- Alicia Boto
- Instituto de Productos Naturales y Agrobiología del CSIC, Avda. Astrofísico Francisco Sanchez 3, 38206-La Laguna, Tenerife, Spain.
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Abstract
[reactions: see text] N-Iodosuccinimide provides a mild, convenient, and tuneable reagent for the selective mono- or didebenzylation in representative, multifunctionalized carbohydrate and amino acid derived N-dibenzylamines with neighboring O-functionality.
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Affiliation(s)
- Elizabeth J Grayson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, South Parks Road, Oxford OX1 3TA, UK
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