Rhodium(III)-Catalyzed Sequential Cyclization of Enaminones with 1,3-Dienes via C–H Activation for the Synthesis of Fluorenones

An efficient method for construction of various fluorenones has been achieved via Rh(III)-catalyzed C–H activation/[4 + 2] annulation/aromatization sequences of simple and readily available enaminones and 1,3-dienes. This protocol showed good substrate compatibility as an array of structurally and electronically diverse fluorenones prepared efficiently in moderate to good yields and preparative scale utility showing very good efficiency in the late-stage functionalization of complex valuable molecules.