Indenes are important core structures in organic chemistry. Few simple arylallenes have been used to construct indene skeletons by Friedel− Crafts reaction. Lewis acid catalyzed reaction of ethenetricarboxylates 1 and arylallenes has been examined in this study. The reaction of arylallenes and ethenetricarboxylate triesters with SnCl4 gave indene derivatives efficiently, via a conjugate addition/Friedel− Crafts cyclization reaction. On the other hand, ...
