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Planarization of 8π Rings. I. Confirmation of a speculation by Ermer on the ground state of a strained cyclooctatetraene and studies on analogous oxepins
Author(s) -
Trindle Carl
Publication year - 1998
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1998)67:6<367::aid-qua3>3.0.co;2-t
Subject(s) - cyclooctatetraene , ring (chemistry) , planarity testing , chemistry , ground state , ring strain , 2 norbornyl cation , ring flip , aromaticity , computational chemistry , crystallography , stereochemistry , molecule , atomic physics , physics , organic chemistry
We describe by ab initio calculations several rings containing eight π electrons, forced into planarity by altering the balance of strain with fused rings. These include a tricyclic fused‐cyclopropano ring derivative of cyclooctatetraene suggested by Ermer to be planar in its ground state, an analogous tricyclic oxepin, and cyclobutano ring‐fused cyclooctatetraene previously described experimentally. We verify that cyclopropano ring fusion planarizes rings with eight π electrons; however, by bond alternation and magnetic susceptibility suppression, forming the planar ring leaves the system anti‐aromatic. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 367–376, 1998