Addition of sulfonylphthalides to para-quinone methides: Selective 1,6-additions and oxidative annulations

(KOBu)-Bu-t mediated addition of sulfonylphthalides to p-quinone methides led to the selective synthesis of isochroman-1,4-diones and addition products. Interestingly, isochroman-1,4-diones were obtained via an unprecedented oxidative annulation pathway. The present work highlights a wide variety of substrates, good yields, shorter reaction time and ambient reaction conditions. Furthermore, a few addition products were transformed into functionalized heterocyclic molecules. Additionally, the scale-up experiment suggests the practical feasibility of preparing isochroman-1,4-diones in higher-scale reactions.

Automated summary

In this study, isochroman-1,4-diones and addition products were selectively synthesized through KOBu-Catalyzed addition of sulfonylphthalides to p-quinone methides. It is noteworthy that isochroman-1,4-diones were obtained via an unprecedented oxidative annulation pathway. The research highlights the broad substrate scope, high yields, shorter reaction time, and mild reaction conditions. Furthermore, some addition products can be transformed into functionalized heterocyclic molecules. Additionally, the scalability experiment demonstrates the practical feasibility of preparing isochroman-1,4-diones in larger scale reactions.