Rhodium-Catalyzed Directing Group-Assisted Annulation of Arene C-H Bond with Vinylene Carbonate toward Isocoumarins

Isocoumarins are an important pharmaceutical compounds. Many synthetic pathways have been developed, mainly focusing on the cyclization of benzoic acid or other with alkynes. Sulfinylidene benzamides were facilely prepared and developed in the chelation-assisted arene ortho-C-H functionalization, and vinylene carbonate can establish an oxidant-free catalytic system, giving carbonic acid as a sole side product. In the presence of rhodium catalyst, an annulation between sulfinylidene benzamides and vinylene carbonate was developed, proceeding with directing group-assisted ortho-C-H coupling and intramolecular alcoholysis toward nonsubstituted isocoumarins in moderate to good yields.

Automated summary

This article presents a simple synthetic method for the pharmaceutical compound isocoumarins. By utilizing the cyclization reaction between sulfinylidene benzamides and vinylene carbonate, along with directing group-assisted ortho-C-H coupling and intramolecular alcoholysis, nonsubstituted isocoumarins can be efficiently synthesized.