Contrasting responses of pyrido[2,1-a]isoindol-6-ones and their sultam counterparts to photochemical activation.

A ring-closing metathesis-based strategy has allowed access to an unreported pair of pyridoisoindolones and their previously unknown sultam counterparts. The synthetic routing takes advantage of the ready availability of N-allylphthalimide and N-allylsaccharin and proceeds via the proper incorporation of small side chains into the heterocyclic ring. Positionally selective introduction of the conjugated diene functionality was realized efficiently.