Premium
Conformational Analysis of Open‐Chain 1,2:3,4‐Diepoxides: Comparison of crystal structures, NMR data, and molecular‐orbital calculations
Author(s) -
Bur Daniel,
Nikles Martin,
Séquin Urs,
Neuburger Markus,
Zehnder Margareta
Publication year - 1993
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19930760506
Subject(s) - chemistry , diastereomer , chain (unit) , molecular orbital , crystallography , solid state , crystal structure , crystal (programming language) , stereochemistry , computational chemistry , molecule , organic chemistry , physics , computer science , programming language , astronomy
Abstract Several pairs of diastereoisomeric open‐chain 1,2:3,4‐diepoxides with different substitution patterns were prepared (see 3–9 ). As far as possible, crystal structures were determined to corroborate the relative configurations and to give insight into the solid‐state conformations of these compounds. The comparison with our earlier molecular‐orbital calculations and with 1 H‐NMR measurements shows that the solid‐state conformations of eight out of the nine open‐chain 1,2:3,4‐diepoxides, whose crystal structures had been determined, correspond to minima on the calculated energy profiles for these compounds or for closely related derivatives. In solution, highly substituted diepoxides of the erythro ‐series ( e ‐ 6 , e ‐ 7 , e ‐ 9 ) seem to prefer the same conformation as in the crystal. The solution conformations of all other diepoxides differ from the arrangement in the solid state.