Skeleton Editing of Indenes With Metal Carbenes to Access 1,2-Dihydronaphthalenes

Single-atom insertion reactions in cyclic scaffolds have garnered unprecedented attention in recent years. Despite significant advances, the direct skeleton editing of planar indene to yield three-dimensional 1,2-dihydronaphthalene via carbon atom insertion remains unknown. Herein, we report a silver-catalyzed skeletal editing strategy that enables the direct insertion of a functionalized carbon atom into indenes, accessing the corresponding 1,2-dihydronaphthalenes by trapping of an α-trifluoromethyl arylcarbene generated from triftosylhydrazone. This transformation is operationally simple, conducted on a preparative scale, and affords products that are amenable to further derivatization. In addition, the first asymmetric single-atom skeleton editing of indenes was accomplished by using a chiral dirhodium catalyst. Comprehensive experimental and computational studies were performed to provide detailed insights into the mechanistic pathway and the origin of enantioselectivity.