Rhodium(I)‐Catalyzed Cycloisomerization of Benzylallene‐Alkynes through CH Activation

Abstract

Abstract The efficient Rh I ‐catalyzed cycloisomerization of benzylallene‐alkynes produced the tricyclo[9.4.0.0 3,8 ]pentadecapentaene skeleton through a C H bond activation in good yields. A plausible reaction mechanism proceeds via oxidative addition of the acetylenic CH bond to Rh I , an ene‐type cyclization to the vinylidenecarbene–Rh I intermediate, and an electrophilic aromatic substitution with the vinylidenecarbene species. It was proposed based on deuteration and competition experiments.