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DFT–GIAO–NBO and 13C NMR study of the δ-syn-axial effect in 2,4-disubstituted adamantanes

✍ Scribed by B. Mikhova; B. Stamboliyska; A. Koch; H. Duddeck; E. Kleinpeter

Publisher
John Wiley and Sons
Year
2008
Tongue
English
Weight
105 KB
Volume
46
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

Six groups of diastereomeric 2,4‐disubstituted adamantanes were studied with DFT–GIAO–NBO (natural orbital analysis) methods. The calculated ^13^C chemical shifts reproduce well the experimental data. It was found that among all diastereomers, those bearing substituents in δ‐syn‐axial positions showed the largest overall deshielding, i.e. the sum of all ^13^C chemical shifts [Σδ(^13^C)] was the greatest and also had the highest delocalization contribution to the molecular energy evaluated with NBO. The higher delocalization energy is proposed to be the origin of the deshielding δ‐syn‐axial effect. Copyright © 2008 John Wiley & Sons, Ltd.

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