By means of the AlCl3-catalyzed reactions of (bi)cycloalkene dianhydrides with toluene, lactones and tricyclic or tetracyclic ketal- lactones were prepared. The nature of the products obtained depends greatly on the solvent, the molar ratio and sequence of addition of the reactants, and the temperature. For the ketal-lactone, AlCl3 promotes the formation of the cyclotautomer of the γ-ketocarboxylic acid intermediate, and the α- hydroxylactone then adds to the unsaturated carbon bond. The endo-aroyl group of the norbornane lactone can readily be transformed to an exo-group at elevated temperature. The structures were established by NMR and X-ray measurements.
|Number of pages||5|
|Publication status||Published - jan. 1 1999|
ASJC Scopus subject areas
- Organic Chemistry