We have located links that may give you full text access.
Density Functional Theory Computational Reexamination of the Anomeric Effect in 2-Methoxy- and 2-Cyano-1,3-dioxanes and 1,3-Dithianes. Stereoelectronic Interactions Involving the Cyano (C≡N:) Group Revealed by Natural Bond Orbital (NBO) Analysis.
Journal of Organic Chemistry 2018 September 8
This study reports DFT geometry optimization of the anancomeric (ring conformationally anchored) axial r2-methoxy- trans-4, trans-6-dimethyl- and r-2-cyano- trans-4, trans-6-dimethyl-1,3-dioxanes (1-ax and 3-ax, respectively), the equatorial isomers (2-eq and 4-eq, respectively), the axial r2-methoxy- and r2-cyano- trans-4, trans-6-dimethyl-1,3-dithianes (5-ax and 7-ax, respectively), and the equatorial isomers (6-eq and 8-eq, respectively). The computational results reproduce the anomeric effect in 1-8, and most importantly, Weinhold's NBO analysis supports the contribution of n(X) → σ*(C-Y) stereoelectronic interactions that stabilize the axial isomers. Furthermore, NBO analysis of delocalization energy E(2) of properly aligned filled/empty orbitals in these isomeric 2-polar-substituted heterocycles reveals that n(O) → σ*(C-Hax ) is responsible for the increased charge density at C(2)-Hax in the equatorial isomers, providing an explanation for the computational observation that very recently led Wiberg, Bailey, Lambert, and Stempel ( J. Org. Chem. 2018, 83, 5242-5255) to discard a potential contribution of n(X) → σ*(C-Y) stereoelectronic interactions that stabilize the axial isomers. Interestingly, during the course of this study, two relevant stereoelectronic interactions involving the cyano group were revealed, n(N) → σ*(NC-C) and σ(C(2)-H) → σ*(C-N).
Full text links
Related Resources
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app
All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.
By using this service, you agree to our terms of use and privacy policy.
Your Privacy Choices
You can now claim free CME credits for this literature searchClaim now
Get seemless 1-tap access through your institution/university
For the best experience, use the Read mobile app