Rh(III)-Catalyzed [3 + 4] Annulation of 3-Arylisoindolinones with 2-Methylidenetrimethylene Carbonate via C–H Activation to Access Isoindolinone Spirobenzoxepines

A Rh(III)-catalyzed C-H activation/annulation of 3-aryl-3-hydroxyisoindolinones with 2-methylidenetrimethylene carbonate has been developed. This method leads to the synthesis of seven-membered isoindolinone spirobenzoxepines through sequential C-C and C-O bond formations, which are interesting scaffolds in drug discovery. Its synthetic application has also been demonstrated to highlight the versatility. In addition, this is the first example in which 2-methylidenetrimethylene carbonate serves as a C3O1 synthon to accomplish [3 + 4] annulation in transition-metal-catalyzed C-H activation reactions.