Solvent‐Free Synthesis of 1,8‐Dioxo‐octahydroxanthenes and 14‐Aryl‐14 H ‐dibenzo[ a,j ]xanthenes using Saccharin SulfonicAcid as an Efficient and Green Catalyst

Saccharin sulfonic acid (SaSA) is utilized as a highly efficient, green and inexpensive sulfonic acid‐containing catalyst for the following one‐pot multi‐component organic transformations: (i) the condensation of dimedone (2 eq.) with aromatic aldehydes (1 eq.) leading to 1,8‐dioxo‐octahydroxanthenes, and (ii) the reaction of 2‐naphthol (2 eq.) with arylaldehydes (1 eq.) leading to 14‐aryl‐14 H ‐dibenzo[ a,j ]xanthenes. In these protocols, the title compounds are produced in high to excellent yields and in relatively short reaction times under solvent‐free conditions.