Journal ArticleDOI
Deoxygenative [1,2]-hydride shift rearrangements in nucleoside and sugar chemistry: analogy with the [1,2]-electron shift in the deoxygenation of ribonucleotides by ribonucleotide reductases.
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A variant of the semipinacol rearrangement that was observed in the laboratory has been applied to the synthesis of several furanose and pyranose derivatives in good yields and demonstrated the absence of remote hydroxyl-group participation.Abstract:
A variant of the semipinacol rearrangement that was observed in our laboratory has been applied to the synthesis of several furanose and pyranose derivatives. The process consists of an "orchestrated" [1,2]-hydride shift with departure of a leaving group from the opposite face. Transient formation of a C=O group is followed by rapid transfer of a hydride-equivalent from the same face from which the leaving group departed, which results in double inversion of stereochemistry at the two vicinal carbon atoms. Treatment of 2'-O- and 3'-O-tosyladenosine with lithium triethylborohydride in DMSO/THF gave the respective 2'- and 3'-deoxynucleoside analogues with beta-D-threo configurations. Identical treatment of 5'-O-TPS-2'-O-tosyladenosine gave 9-(5-O-TPS-2-deoxy-beta-D-threo-pentofuranosyl)adenine. The same [1,2]-hydride shift and stereochemistry with the 5'-OH and 5'-O-TPS compounds demonstrated the absence of remote hydroxyl-group participation. Application of this process to other nucleoside 2'-O-tosyl derivatives gave the 2'-deoxy-threo compounds in good yields. The reaction-rate order was OTs approximately Br >> Cl for 2'-O-tosyladenosine, 2'-bromo-2'-deoxyadenosine, and 2'-chloro-2'-deoxyadenosine (all with beta-d-ribo configurations). Analogous results were obtained with mannopyranoside derivatives with either 4,6-O-benzylidene protection or a free OH group at C4. Deuterium labeling clearly defined the stereochemical course as a cis-vicinal [1,2]-hydride shift on the face opposite to the original cis OH and OTs groups followed by hydride transfer from the face opposite to the [1,2]-hydride shift. Synthetic and mechanistic considerations are discussed.read more
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Fluorinated Nucleosides: Synthesis and Biological Implication
TL;DR: The present review deals with the synthetic methodology, structural and biological implication of carbohydrate-modified fluoronucleosides.
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Synthesis of rare sugar isomers through site-selective epimerization.
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Chemo- and Regioselective Monosulfonylation of Nonprotected Carbohydrates Catalyzed by Organotin Dichloride under Mild Conditions
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Reference EntryDOI
The Barton-McCombie Reaction
TL;DR: A detailed description and comparison of the combinations of substrates and reagents that will bring about these processes and provides a summary and evaluation of alternative deoxygenation methods can be found in this paper.
Journal ArticleDOI
Convenient syntheses of 3'-amino-2',3'-dideoxynucleosides, their 5'-monophosphates, and 3'-aminoterminal oligodeoxynucleotide primers.
Ralf Eisenhuth,Clemens Richert +1 more
TL;DR: 5'-Protected 3'-amino-2',3'-dideoxynucleosides containing any of the four canonical nucleobases (A/C/G/T) were prepared via azides, providing starting materials for the preparation of labeled or photolably protected monomers for chemical primer extension, an inexpensive methodology for genotyping and labeling.
References
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Journal ArticleDOI
Preparation and Synthetic Utility of Some Organotin Derivatives of nucleosides
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Deoxygenation of Alcohols Employing Water as the Hydrogen Atom Source
TL;DR: Evidence for fundamentally novel and previously overlooked modes of reactivity for water and trialkylboranes of wide ranging importance in both theoretical and applied investigations is provided.
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Synthesis and anti-HIV activity of different sugar-modified pyrimidine and purine nucleosides.
Piet Herdewijn,Jan Balzarini,Masanori Baba,Rudi Pauwels,Arthur Van Aerschot,Gerard Janssen,Erik De Clercq +6 more
TL;DR: Pyrimidine derivatives emerged as the most potent and/or selective inhibitors of HIV-induced cytopathogenicity and 3'-fluoro-2,6-diaminopurine 2',3'-dideoxynucleoside (FddDAPR) were the most selective inhibitor of HIV replication.
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Facile reduction of alkyl tosylates with lithium triethylborohydride. An advantageous procedure for the deoxygenation of cyclic and acyclic alcohols
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Regiospecific metal-catalyzed ring expansion of aziridines to .beta.-lactams
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