Convenient synthesis of new polysubstituted isoindole-1,3-dione analogues

Three new polysubstituted isoindole-1,3-diones were prepared from 2-ethyl-5-hydroxy-3a,4,5,7a-tetrahydro-isoindole-1,3-dione. The reaction of 2-ethyl-5-hydroxy-3a,4,5,7a-tetrahydro-isoindole-1,3-dione with m-CPBA gave the corresponding epoxide. The triacetate derivative was obtained via cis-hydroxylation using OsO4, followed by acetylation. An aromatic derivative, a secondary reaction product, was also formed during the acetylation. Finally, a tricyclic derivative from 2-ethyl-5-hydroxy-3a,4,5,7a-tetrahydro-isoindole-1,3-dione was synthesized via dichloroketene addition under microwave irradiation. The exact structures of epoxide and tricyclic derivatives were determined by X-ray diffraction analysis.