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.