Ring Expansion toward Disila‐carbocycles via Highly Selective C−Si/C−Si Bond Cross‐Exchange

Herein, we successfully inhibited the preferential homodimerization and C−Si/Si−H bond cross‐exchange of benzosilacyclobutenes and monohydro‐silacyclobutanes and achieved the first highly selective C−Si/C−Si bond cross‐exchange reaction by deliberately tuning the Ni‐catalytic system, which constitutes a powerful and atom‐economical ring expansion method for preparing medium‐sized cyclic compounds bearing two silicon atoms at the ring junction, which are otherwise inaccessible. The DFT calculation explicitly elucidated the pivotal role of Si−H bond at silacyclobutanes and the high ring strain of two substrates in realizing the two C−Si bonds cleavage and reformation in the catalytic cycle. We have developed the intermolecular σ‐bond exchange reaction of two different C−Si bonds with high cross‐redistribution selectivity, which serves as a ring expansion protocol to assemble diverse disila‐carbocycles. Mechanistic studies confirmed that the presence of hydrogen on silicon of silacyclobutanes and the high ring strain for both of two substrates are critical to ensure the desired reactivity and selectivity.