Synthesis of fluorocyclobutanones and their use in the synthesis of fluoronucleosides

Ghazi, Hedieh; Lee‐Ruff, Edward

doi:10.1016/j.jfluchem.2005.09.007

Cited by 7 publications

(6 citation statements)

References 30 publications

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“…The van der Waals volume of CF 3 is slightly larger than for CH 3 (atomic radii of 1.35 Å for F vs 1.17 Å for H) . Coupled with the larger dipolar nature of the C–F bond results in significant repulsion in 1 R=CF 3 as compared to 1 R=CH 3 in their gauche conformations as shown by their crystal structures and computation.…”

Section: Discussionmentioning

confidence: 96%

Photochemical Generation of 9H‐Fluorenyl Radicals

Dyblenko

Chtchemelinine

Reiter

et al. 2014

Photochem & Photobiology

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A series of 9-substituted fluorenols and 9,9'-disubstituted-9,9'-bifluorenyls were irradiated to give products derived from fluorenyl radicals. Product distribution was solvent dependent. A TEMPO adduct was isolated from the photoexcitation of 9-fluorenol. An unusual unsymmetrical 3,9'-bifluorenyl was observed from the photolysis of 9-trifluoromethylfluorenol and 9,9'-di(trifluoromethyl)-9,9'-bifluorenyl in more polar or hydrogen-bonding solvents. The electronic nature of 9-substituted fluorenyl radicals was probed using theoretical calculations showing the dipolar character of species with electron-deficient groups. These constitute the first examples of "doubly destabilized" radicals.

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Section: Discussionmentioning

confidence: 96%

Photochemical Generation of 9H‐Fluorenyl Radicals

Dyblenko

Chtchemelinine

Reiter

et al. 2014

Photochem & Photobiology

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“…Photocyclo-elimination is known to accompany ring-expansion, the latter pathway leading to a substituted ketene which could oligomerize or produce carboxylic acids on work up [ 16 ]. The regioselectivity for insertion of the oxacarbene to the N-9 position has been established from previous studies [ 6 , 8 , 9 , 10 , 11 ] with the predominant presence of the N-9(H) tautomer in solution. The major epimer was shown to possess the exo stereochemistry on the basis of 1D and 2D (HSQC, COSY and NOESY).…”

Section: Resultsmentioning

confidence: 97%

“…The general synthetic protocols involve the use of monosaccharide chirons which are coupled to heterocycles employing a key glycosylation step which is often not stereoselective. During the last decade our group has developed a photochemical glycosylation method based on the photoisomerization of cyclobutanones to transient 2-tetrahydrofuranylidenes and their insertion into alcohols [ 5 ] or weakly acidic N-H functions ( Scheme 1 ) [ 6 , 7 , 8 , 9 , 10 , 11 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

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Photochemical Synthesis of Nucleoside Analogues from Cyclobutanones: Bicyclic and Isonucleosides

2010

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The preparation of two nucleoside analogues are reported. Both syntheses involve a key photochemical ring-expansion of cyclobutanones to an oxacarbene and its subsequent scavenging by 6-chloropurine. The synthesis of a bicyclic (locked) purine starts from a oxabicycloheptanone with a hydroxymethyl pendant. The preparation of an isonucleoside uses a cyclobutanone with an α-substituted 6-chloropurine. Irradiation of the latter produces an isonucleoside and acyclic nucleoside analogues.

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“…178 Their synthesis commenced with the hydroxymethylcyclobutanone 331, which was fluorinated with DAST to yield the 3-fluoromethylcyclobutanone 332 in 60% yield (Scheme 59). The fluoromethylated derivative 332 was subjected to UV irradiation in the presence of 6-chloropurine to afford the fluoronucleoside analogue 333 and its a anomer.…”

Section: 0 -Monofluoromethylated Nucleosidesmentioning

confidence: 99%