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Spectroscopic and Theoretical Investigations of Bicyclic Dioximes and Dimethoximes with Eight‐Membered Rings
Author(s) -
Strenge Andrea,
Rademacher Paul
Publication year - 1999
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199907)1999:7<1611::aid-ejoc1611>3.0.co;2-a
Subject(s) - bicyclic molecule , chemistry , octane , ring (chemistry) , aromaticity , stereochemistry , molecule , ab initio , nonane , computational chemistry , organic chemistry
The bicyclic dioximes 4–6 and dimethoximes 7–9 , which contain the functional groups in opposite positions of bridged eight‐membered rings, were synthesized. Their conformational properties and transannular interactions were investigated by spectroscopic (PE, 13 C NMR) and theoretical (MMX, AM1, ab initio HF, and B3LYP) methods. While in the 3,7‐disubstituted bicyclo[3.3.1]nonane derivatives 5 and 8 the eight‐membered ring has a CC conformation favourable for through‐space interactions of the π(CN) orbitals, in the bicyclo[3.3.0]octane derivatives 4 and 7 as well as the 2,6‐disubstituted bicyclo[3.3.1]nonanes 6 and 9 the functional groups are in geometric orientations that are unfavourable for such interactions. Through‐space orbital interactions in the molecules with favourable conformations lead to a splitting of the π(CN) MOs of 0.4–0.6 eV.