Open analogues of arcyriaflavin A. Synthesis through Diels-Alder reaction between maleimides and 1-aryl-3-tert-butyldimethylsiloxy-1,3-butadienes

The preparation of a range of open analogues of arcyriaflavin A is describe d. The synthetic approach is based on the use of perhydroisoindole-1,3,5-tr iones as key intermediates, which were obtained via Diels-Alder methodology using 1-aryl-3-siloxy-1,3-butadienes as starting materials. Fischer indoli zation and aromatization processes afforded different methoxy-substituted a rylpyrrolocarbazoles. The stereochemistry and conformation of the Diels-Ald er products and the regiochemistry of the indolization reactions are suppor ted by NMR and molecular modeling studies.