Synthesis of Non-symmetrical Dispiro-1,2,4,5-Tetraoxanes and Dispiro-1,2,4-Trioxanes Catalyzed by Silica Sulfuric Acid

A novel protocol for the preparation of nonsymmetrical 1,2,4,5-tetraoxanes and 1,2,4-trioxanes, promoted by the heterogeneous silica sulfuric acid (SSA) catalyst, is reported. Different ketones react under mild conditions with gemdihydroperoxides or peroxysilyl alcohols/beta-hydroperoxy alcohols to generate the corresponding endoperoxides in good yields. Our mechanistic proposal, assisted by molecular orbital calculations, at the.B97XD/def2-TZVPP/PCM(DCM)// B3LYP/6-31G(d) level of theory, enhances the role of SSA in the cyclocondensation step. This novel procedure differs from previously reported methods by using readily available and inexpensive reagents, with recyclable properties, thereby establishing a valid alternative approach for the synthesis of new biologically active endoperoxides.

Automated summary

A novel protocol for the synthesis of nonsymmetrical 1,2,4,5-tetraoxanes and 1,2,4-trioxanes using heterogeneous silica sulfuric acid (SSA) catalyst has been reported. The method involves different ketones reacting under mild conditions to generate corresponding endoperoxides in good yields, with the assistance of molecular orbital calculations. This approach provides a valid alternative for the synthesis of new biologically active endoperoxides using readily available and inexpensive reagents with recyclable properties.