Access to indenones by rhodium(III)-catalyzed C-H annulation of arylnitrones with internal alkynes.

Under redox-neutral conditions, rhodium(III)-catalyzed C-H annulation of N-tert-butyl-α-arylnitrones with internal alkynes has been realized for the synthesis of indenones under mild conditions. This reaction proceeded in moderate to high yields and with good functional group tolerance.