Thermisches Verhalten von o-Dipropenylbenzol, Beispiel einer aromatischen [1,7]-sigmatropischen H-Verschiebung. Vorläufige Mitteilung

✍ Scribed by H. Heimgartner[1]; H.-J. Hansen; H. Schmid

• Publisher: John Wiley and Sons
• Year: 1970
• Tongue: German
• Weight: 229 KB
• Volume: 53
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19700530124

✦ Synopsis

Abstract

cis, cis‐, cis, trans‐ and trans, trans‐o‐Dipropenylbenzene (cis, cis‐, cis, trans‐ and trans, trans‐1) were prepared. At 225° cis, cis‐1 isomerises to give cis, trans‐1 and vice versa. The isomerisation follows 1. order kinetics. At equilibrium 89% cis, trans‐ and 11% cis, cis‐1 are present. It is shown by deuterium labelling that the isomerisation is due to aromatic [1, 7 a] sigmatropic H‐shifts. trans, trans‐1 rearranges at 225° to yield 2, 3‐dimethyl‐1, 2‐dihydronaphthalene (3). This can be visualized by disrotatory ring closure of trans, trans‐1 followed by an aromatic [1, 5 s] H‐shift. When cis, cis‐ or cis, trans‐1 are heated for 153 hrs at 225° a small amount (3%) of 1‐ethyl‐1,2‐dihydronaphthalene (5) is formed.