Manganese(I)-Catalyzed Synthesis of Fused Eight- and Four-Membered Carbocycles via C-H Activation and Pericyclic Reactions.

Pericyclic reactions have allowed facile construction of complex cycles. On the other hand, metal-catalyzed C-H activation has been established as an important strategy for rapid synthesis of complex structures. The two areas are integrated in Mn(I)-catalyzed redox-neutral coupling of 3-alkenyl- and 3-allylindoles with propargylic carbonates, which occurred via C-H allenylation with subsequent pericyclic reactions to afford fused eight- and four-membered carbocycles, respectively.