Acid-catalysed intramolecular Friedel-Crafts annulation of hetero-atom-functionalized para-quinone methides: access to O-, S- and N-based heterocycles.

ABSTRACT

We describe here an acid-mediated one-pot approach to access substituted xanthene and thioxanthane derivatives from ortho-heteroaryl phenyl-substituted para-quinone methides via 1,6 intramolecular arylation. The scope of this work was further elaborated to the synthesis of 10H-indolo[1,2-a]indole-based heterocyclic systems using indole based para-quinone methides.