Conformational Analysis of Open-Chain 1,2:3,4-Diepoxides: Comparison of crystal structures, NMR data, and molecular-orbital calculations

✍ Scribed by Daniel Bur; Martin Nikles; Urs Séquin; Markus Neuburger; Margareta Zehnder

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: German
• Weight: 780 KB
• Volume: 76
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19930760506

✦ Synopsis

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.