A Benzyne Route to Xanthones and Thioxanthones

Significance

A tandem reaction of salicylic esters and thiosalicylic esters with in situ benzyne, generated from the reaction of o-(trimethylsilyl)phenyl triflate with CsF, leads to the formation of xanthones and thioxanthones from readily available starting materials in reasonable to good yields. The conditions are mild and the regioselectivity, as evidenced in the formation of relevant xanthones (R¹, R⁴, R⁵ = H, R³ = OMe), is high.