Conversion of the Enantiomers of Spiro[4.4]nonane-1,6-Diol into Both Epimeric Carbaspironucleosides Having Natural C1‘ Absolute Configuration

Paquette, Leo A.; Hartung, Ryan E.

doi:10.1021/ol0340033

Cited by 17 publications

(7 citation statements)

References 23 publications

(25 reference statements)

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“…Among the synthetic issues that have since been addressed are those of devising workable approaches to analogues bearing a modified 2‘-deoxyribose moiety such as 5 . As matters progressed, a practical route to enantiomerically pure spiro[4.4]nonanes 6 has been realized …”

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confidence: 99%

Stereoselective Synthesis of Conformationally Constrained 2‘-Deoxy-4‘-thia β-Anomeric Spirocyclic Nucleosides Featuring Either Hydroxyl Configuration at C5‘

Dong

Paquette

2005

J. Org. Chem.

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An enantioselective approach to 2'-deoxy-4'-thia spirocyclic nucleosides featuring an alpha- or beta-hydroxyl substituent at C-5' of the carbocyclic ring is detailed. The starting point is the mandelate acetal 8. The overall strategy involves the stereocontrolled dihydroxylation of this dihydrothiophene, subsequent generation of the keto acetonide 12 followed by its Meerwein-Ponndorf-Verley reduction and beta-elimination, protection of the resulting dihydroxy thiaglycal, electrophilic glycosidation according to the Haraguchi protocol, reductive removal of the phenylseleno group, and end-game global deprotection. Acquisition of the alpha- and beta-5'-isomers is equally facile. Various 1D and 2D NMR techniques are used for assigning configuration.

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confidence: 99%

Stereoselective Synthesis of Conformationally Constrained 2‘-Deoxy-4‘-thia β-Anomeric Spirocyclic Nucleosides Featuring Either Hydroxyl Configuration at C5‘

Dong

Paquette

2005

J. Org. Chem.

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“…Our own search for antiviral therapeutic agents has involved the synthesis of various classes of spirocyclic nucleosides, 7 ranging from those that carry conventional furanoside features 8 to their thia 9 and carba counterparts. 10 To complement the predescribed approaches to dideoxy and didehydrodideoxy analogues, we have more recently targeted mimics bearing a modified 2′-deoxyribose moiety. The synthetic chemistry surrounding this effort constitutes the subject matter of the present report.…”

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Stereochemical Features of Lewis Acid-Promoted Glycosidations Involving 4‘-Spiroannulated DNA Building Blocks

et al. 2004

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Tin tetrachloride-catalyzed glycosidation of persilylated nucleobases with acetate donor 6 in CH(2)Cl(2) solution followed by deprotection gave rise very predominantly to alpha-spironucleosides. These stereochemical assignments stem from the determination of NOE interactions and an X-ray crystallographic analysis of the latter product. Computational studies revealed that these results are consistent with the fact that the C5' substituent shields the beta-face of the oxonium ion involved in the coupling reaction while the C3' substituent is projected away from the alpha-underside. Attack from the more open direction is therefore kinetically favored. Entirely comparable calculations suggested that donor 19 should behave comparably. Experimentation involving this donor gave results consistent with this model although more equitable alpha/beta spironucleoside product ratios were seen when acetonitrile was employed as the reaction medium.

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“…[140,141], meanwhile Paquette et al [142] described the synthesis of epimeric carbaspironucleosides 279 and 280 (Scheme 33).…”

Section: ) Carbocyclic Nucleosides With a Bicyclic Ring Sugarmentioning

confidence: 99%

An Overview of Diazine Nucleoside Analogues

Agrofoglio

2006

COC

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Early work on antiviral agents focused on traditional nucleoside analogues in which the base was linked to one or other of the naturally occurring sugars. Some of these were indeed shown to possess anti-metabolic properties, but it became apparent that their usefulness was severely limited by instability and poor selectivity. Since the discovery of the first successful anti-viral drug, acyclovir, in 1974 by Gertrude "Trudy" Elion, interest has diversified towards compounds in which the heterocycle and sugar components of the nucleoside differ significantly from the natural form. These novel types of nucleosides act as anticancer, antiviral or antibacterial drugs. The intense search for clinically useful nucleoside derivatives has resulted in a wealth of new approaches for their synthesis. In this review, we will give an overview of the synthesis of some pyrimidine nucleosides according to their structural types (e.g., acyclics, carbocyclics, and C5-substituted pyrimidine nucleosides), including compounds having "unnatural" L-stereochemistry, along with the synthetic routes of some selected examples. The article also refers to other relevant review articles that have covered particular areas of investigation or have dealt in depth with a single compound.

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Conversion of the Enantiomers of Spiro[4.4]nonane-1,6-Diol into Both Epimeric Carbaspironucleosides Having Natural C1‘ Absolute Configuration

Abstract: [reaction: see text] The enantiomers of spiro[4.4]nonane-1,6-diol have been transformed by different reaction pathways into the two possible carbaspironucleoside epimers with natural C1' absolute stereochemistry.

Cited by 17 publications

References 23 publications

Stereoselective Synthesis of Conformationally Constrained 2‘-Deoxy-4‘-thia β-Anomeric Spirocyclic Nucleosides Featuring Either Hydroxyl Configuration at C5‘

Stereoselective Synthesis of Conformationally Constrained 2‘-Deoxy-4‘-thia β-Anomeric Spirocyclic Nucleosides Featuring Either Hydroxyl Configuration at C5‘

Stereochemical Features of Lewis Acid-Promoted Glycosidations Involving 4‘-Spiroannulated DNA Building Blocks

An Overview of Diazine Nucleoside Analogues

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