Electrophilic ipso-substitution reactions between 1,3,6-tritert- butylazulcne (2) and several electrophilic reagents were examined. Friedel-Crafts and Vilsmeier reactions of 2 gave the corresponding ipso-substitution products in moderate to excellent yields. One of the ipso-substitution products, 1,6- di-tert-butyl-3-formylazulene (5), was converted in high yield into the synthetically more useful azulene derivative 1,6-di-tert-butylazulene (1) by decarbonylation on treatment with pyrrole in acetic acid. Treatment of 2 with N-[(trifluoromelhyl)su]fonyl]pyridinium trifluoromethanesulfonate (TPT) unexpectedly afforded 1- trifluoromethylthioazulene 10 and l(8H)-azulenone 11. Compound 2 also reacted with tetracyanoethylene (TCNE) to give an excellent yield of cycloaddition product 13, rather than the ipso-substitution reaction product.
|Number of pages||10|
|Journal||European Journal of Organic Chemistry|
|Publication status||Published - 2009 Apr|
- Aromatic substitution
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry