A convenient one-pot preparation of spiro[fluorene-9,9′-xanthene]-3′,6′-diol derivatives

Spiro[fluorene-9,9'-xanthene]-3',6'-diol derivatives were prepared via the condensation reaction of fluorenones with resorcinol using p-toluenesulfonic acid as catalyst. A series of substituted spiro[fluorene-9,9'-xanthene]-3',6'-diol derivatives with halogen, alkyl, phenyl, and ester were prepared by this one-pot method in good yield.