The solvent-controlled Rh(iii)-catalyzed switchable [4+2] annulation of 2-arylIndoles with iodonium ylides

Highly selective and switchable [4+2] annulations of 2-arylindoles with iodonium ylides were achieved by performing solvent-controlled Rh(III)-catalyzed C-H activations. When using DCM as a solvent, the C-H functionalization of 2-arylindoles with iodonium ylides selectively delivered indolo[2,1-a]isoquinoline derivatives. In contrast, the same catalytic system with a polar HFIP solvent predominately provided benzo[a]carbazole moieties.