REGIOSELECTIVE FUNCTIONALIZATIONS AND CONFORMATIONAL STUDIES OF DI-O-ISOPROPYLIDENE-MYO-INOSITOL DERIVATIVES
SCIE
SCOPUS
- Title
- REGIOSELECTIVE FUNCTIONALIZATIONS AND CONFORMATIONAL STUDIES OF DI-O-ISOPROPYLIDENE-MYO-INOSITOL DERIVATIVES
- Authors
- CHUNG, SK; RYU, YH
- Date Issued
- 1994-05-20
- Publisher
- ELSEVIER SCIENCE BV
- Abstract
- (+/-)-1,2:4,5-Di-O-isopropylidene-myo-inositol (5) and (+/-)-1,2:5,6-di-O-isopropylidene-myo-inositol (6) could be regioselectively functionalized in reactions including alkylation, acylation, and silylation at HO-3 in preference to HO-6 and HO-4, respectively, under specific conditions. The presence of intramolecular hydrogen bonding was evident in IR and H-1 NMR spectra, and the HO-3 group was identified as the hydrogen-bonding donor in 5 and 6. In their crystalline states, diol 5 prefers a chair conformation and diol 6 a twist boat (skew) conformation. Both compounds appear to have substantial populations of chair conformations in the gas and solution phases, on the basis of the MM-2 energy minimizations and comparisons of vicinal coupling constants observed in the 1H NMR spectra (in CDCl3 and Me(2)SO-d(6)) and calculated from the crystal and MM-2 conformations. It is suggested as an explanation for the observed selectivities that the kinetic acidity of the HO-3 group may be enhanced through its intramolecular hydrogen bonding with the cis-vicinal oxygen, or the nucleophilicity of the 3-alkoxide may be enhanced due to its interaction with the cis-vicinal oxygen in a manner similar to the through-space alpha-effect.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/21958
- DOI
- 10.1016/0008-6215(94)84082-2
- ISSN
- 0008-6215
- Article Type
- Article
- Citation
- CARBOHYDRATE RESEARCH, vol. 258, page. 145 - 167, 1994-05-20
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