A 2:1 Coupling Reaction of Arynes with Aldehydes via o-Quinone Methides: Straightforward Synthesis of 9-Arylxanthenes

[reaction: see text] A novel coupling reaction, where an aldehyde and two molar amounts of an aryne are assembled selectively, has been demonstrated to afford diverse 9-arylxanthene derivatives in one step. o-Quinone methide arising from the [2 + 2] cycloaddition of an aldehyde with an aryne was postulated as a transient intermediate.