Structures and Energetics of Two Bridgehead Lactams and Their N- and O-Protonated Forms: An ab Initio Molecular Orbital Study

Document Type

Article

Publication Date

7-1-1993

Abstract

Ab initio molecular orbital calculations optimized with the 6-31G* basis set were employed to investigate the structures, resonance energies, and protonation sites of the two bridgehead bicyclic lactams l-azabicyclo[2.2.2]-octan-2-one (2-quinuclidone) and l-azabicyclo[3.3.1]nonan-2-one. The structures and resonance energies reflect the absence of resonance stabilization in the first molecule and somewhat reduced resonance in the second molecule. While planar amides protonate on oxygen, 2-quinuclidone very strongly favors N-protonation while the N- and O-protonated forms in the 3.3.1 system are almost equal in energy. Discussion of structures and energies is given in the context of resonance theory. © 1993, American Chemical Society. All rights reserved.

Identifier

0000367154 (Scopus)

Publication Title

Journal of the American Chemical Society

External Full Text Location

https://doi.org/10.1021/ja00068a064

e-ISSN

15205126

ISSN

00027863

First Page

6951

Last Page

6957

Issue

15

Volume

115

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