Abstract
A computational investigation of anomeric effects in piperidine rings bearing fluoro and trifluoromethyl substituents shows for both compounds the most pronounced evidence of the anomeric effect, as expressed as hyperconjugative delocalization of the nitrogen lone pair, in structures with the substituent in the axial position and the N–H bond in the equatorial position. This structure is the lowest-energy structure in the fluoro case but not in the trifluoromethyl case where there is an increased axial penalty associated with the CF3 group. The anomeric effect is characterized via geometrical evidence, natural bond orbital analysis, electrostatic effects, and energetic criteria. Computational results from a variety of levels of theory are presented including CCSD(T) with complete basis set extrapolation, B2PLYP-D, ωB97XD, B97-D, M06-2X, B3LYP, and MP2 allowing for a comparison of performance. The CCSD(T)/CBS results are very well represented by either B2PLYP-D or ωB97XD with moderate to large basis sets (aug-cc-pVTZ or aug-cc-pVDZ). Hyperconjugation, electrostatic effects, and steric effects play a role in the relative energetic ordering of the isomers considered.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Additional information
Dedicated to the memory of Professor Isaiah Shavitt and published as part of the special collection of articles celebrating his many contributions.
Rights and permissions
Copyright information
© 2016 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Erxleben, N.D., Kedziora, G.S., Urban, J.J. (2016). Anomeric effects in fluoro and trifluoromethyl piperidines: a computational study of conformational preferences and hydration. In: Shepard, R., Pitzer, R., Dunning, T. (eds) Isaiah Shavitt. Highlights in Theoretical Chemistry, vol 9. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-48148-6_27
Download citation
DOI: https://doi.org/10.1007/978-3-662-48148-6_27
Received:
Accepted:
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-662-48147-9
Online ISBN: 978-3-662-48148-6
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)