Catalytic [2 + 2 + 2] and Thermal [4 + 2] Cycloaddition of 1,2-Bis(arylpropiolyl)benzenes

We have determined that a cationic rhodium(I)/Segphos
complex catalyzes an enantio- and diastereoselective intermolecular [2 + 2 + 2] cycloaddition of 1,2-bis(arylpropiolyl)benzenes with various monoalkynes at room temperature
to give axially chiral 1,4-teraryls possessing an anthraquinone
structure in good yields with good enantio- and diastereoselectivities. We have also determined that a thermal
intramolecular [4 + 2] cycloaddition of 1,2-bis(arylpropiolyl)benzenes proceeds at 60 °C to give aryl-substituted
naphthacenediones in moderate to good yields.