Ryo Shintani

A palladium‐catalyzed skeletal rearrangement of 2‐(2‐allylarylsilyl)aryl triflates has been developed to give highly fused tetrahydrophenanthrosilole derivatives via unprecedented 1,5‐C−Pd/C−Si bond exchange. The reaction pathways can be switched toward 4‐membered ring‐forming C(sp 2 )−H alkylation by tuning the reaction conditions to give completely different products, fused dihydrodibenzosilepin derivatives, from the same starting materials. The inspection of the reaction conditions revealed the importance of carboxylates in promoting the C−Pd/C−Si bond exchange.