An Efficient Solvent Free Synthesis of 1,8-Dioxo-octahydroxanthene Using p-Toluene Sulfonic Acid

A simple and efficient method for the synthesis of 1,8‐dioxo‐octahydroxanthene by using p‐toluenesulfonic acid as a catalyst under solvent free conditions is described, which involves cyclization of 2,2‐arylmethylenebis(3‐hydroxy‐5,5‐dimethyl‐2‐cyclohexene‐1‐one) that was obtained firstly by the reaction of dimedone with aromatic aldehydes in water as solvent and catalyst at room temperature. The experimental procedures in the two steps are very simple and the products are formed in excellent yields.