Cascade Nucleophilic Addition−Cyclic Michael Addition of Arynes and Phenols/Anilines Bearing Ortho α,β-Unsaturated Groups: Facile Synthesis of 9-Functionalized Xanthenes/Acridines

A facile synthesis of xanthenes and acridines based on a cascade nucleophilic addition-cyclic Michael addition process of arynes and phenols/anilines substituted with alpha,beta-unsaturated groups at the ortho positions is described. The reaction has also been successfully extended to the synthesis of 9-spiro-xanthene and acridine derivatives with potential biochemical interest.