DFT Study on 3-Substituted Tetrahydropyran-2-yl Radicals

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Title:DFT Study on 3-Substituted Tetrahydropyran-2-yl Radicals
Creators:
Kozmon, Stanislav
Tvaroška, Igor
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 71, 10, pp. 1453-1469
Uncontrolled Keywords:Radicals, Molecular modeling, <i>Ab initio</i>, Quasi-homoanomeric effect, Tetrahydropyrans, DFT calculations, Conformational analysis, ESR spectroscopy, Carbohydrates

Abstract

A series of tetrahydropyran-2-yl radical (<strong>1</strong>) analogs was studied using density functional theory (DFT) to model conformational behavior of glycopyranosyl radicals. Calculations of the structure and stability of the <sup>4</sup><i>C</i><sub>1</sub>, <sup>1</sup><i>C</i><sub>4</sub>, <i>B</i><sub>2,5</sub>, <sup>O,3</sup><i>B</i>, and <sup>4</sup><i>H</i><sub>3</sub> ring conformers for tetrahydropyran-2-yl radical (<strong>1</strong>) and for 3-fluoro- (<strong>2</strong>, <strong>7</strong>), 3-hydroxy- (<strong>3</strong>, <strong>8</strong>), 3-methoxy- (<strong>4</strong>, <strong>9</strong>), 3-acetoxy- (<strong>5</strong>, <strong>10</strong>), and 3-(benzyloxy)tetrahydropyran-2-yl (<strong>6</strong>, <strong>11</strong>) derivatives showed that conformational behavior of the 3-substituted radicals depends on both the electronic character and orientation of the C3 substituent. The calculations show that radical <strong>1</strong> is slightly pyramidal and exists as an equilibrium mixture of the <sup>4</sup><i>C</i><sub>1</sub> and <sup>1</sup><i>C</i><sub>4</sub> conformers. Substituents at the C3 position force <strong>2</strong>-<strong>11</strong> radicals to adopt a chair conformation with the substituent in the axial orientation. Thus radicals <strong>2</strong>-<strong>6</strong> prefer the <sup>1</sup><i>C</i><sub>4</sub> conformer though there are several ring conformers in equilibrium whereas for radicals <strong>7</strong>-<strong>11</strong> the <sup>4</sup><i>C</i><sub>1</sub> conformer predominates. The calculated preferences are consistent with available ESR data. These results provide further support for the importance of quasi-homoanomeric interactions on stability of anomeric radicals. <p>

Title:DFT Study on 3-Substituted Tetrahydropyran-2-yl Radicals
Creators:
Kozmon, Stanislav
Tvaroška, Igor
Uncontrolled Keywords:Radicals, Molecular modeling, <i>Ab initio</i>, Quasi-homoanomeric effect, Tetrahydropyrans, DFT calculations, Conformational analysis, ESR spectroscopy, Carbohydrates
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:71
Number:10
Page Range:pp. 1453-1469
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20061453UNSPECIFIED
ID Code:2554
Item Type:Article
Deposited On:06 Feb 2009 17:19
Last Modified:06 Feb 2009 16:19

Citation

Kozmon, Stanislav; Tvaroška, Igor (2006) DFT Study on 3-Substituted Tetrahydropyran-2-yl Radicals. Collection of Czechoslovak Chemical Communications, 71 (10). pp. 1453-1469. ISSN 0010-0765

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