The temperature dependence of the 1H n.m.r. spectra of a number of heterocyclic analogues (3a–c) of 12,13-dihydro-11H-dibenzo[a, e]cyclononene has been interpreted in terms of the interconversion of chair- and boat-like conformations. Conformational analysis on these molecules has been carried out with the aid of strain energy calculations on the thia-analogue (3c); in this case a useful correlation between calculated and experimental activation parameters was found. Variable temperature 1H n.m.r. spectroscopy and strain energy calculations have demonstrated that the heterocyclic analogues (4a–f) and (5a–d) of 6,11,12,13-tetrahydro-5H-dibenzo[a, f]-cyclononene and 5,6,7,12,13,14-hexahydrodibenzo[a, f]cyclodecene, respectively, all adopt flexible chair-like conformations with C2 symmetry which undergo an inversion process involving torsion about single bonds.
|Original language||English (US)|
|Number of pages||12|
|Journal||Journal of the Chemical Society, Perkin Transactions 1|
|State||Published - 1976|
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