Bsi(OTf)3-mediated tandem annulation of 1-aryl isochroman-3-ones with oxygenated arenes: one-pot synthesis of polyoxygenated homotriptycenes.

Bi(OTf)3 (bismuth triflate)-mediated one-pot tandem annulation of oxygenated 1-aryl isochroman-3-ones with oxygenated arenes provides polyoxygenated homotriptycenes in moderate to good yields in MeNO2 at reflux (101 °C) for 10 h under an air atmosphere and easy-operational conditions via intermolecular and intramolecular Friedel-Crafts type procedures. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via three carbon-carbon (C-C) bond formations.