“…When 2 is reacted with C 6 H 6 in TfOH, 17 is formed as the major product in 90% yield (eq 3). Similar to the conversion of 3 to 13 , condensation at the ketone group of 2 is followed by a dehydrative-decarbonylation to give the dication 16 , and reaction of 16 with a third benzene is followed by a cyclization to provide 17
…”