Palladium-Catalyzed (4 + 4) Annulation of Silacyclobutanes and 2‑Iodobiarenes to Eight-Membered Silacycles via C–H and C–Si Bond Activation

Construction of eight-membered silacycles via Pd-catalyzed (4 + 4) annulation of silacyclobutanes and 2-iodobiphenyl derivatives is described. This strategy involves direct C–H and C–Si bond activation followed by a ring annulation and features low catalyst loading, ligand-free conditions, and readily available starting materials. Mechanistic studies revealed the involvement of five-membered palladacycle species in the reaction.