Rhodium‐Catalyzed Intramolecular C−H Silylation by Silacyclobutanes

Silacyclobutane was discovered to be an efficient C−H bond silylation reagent. Under the catalysis of Rh I /TMS‐segphos, silacyclobutane undergoes sequential C−Si/C−H bond activations, affording a series of π‐conjugated siloles in high yields and regioselectivities. The catalytic cycle was proposed to involve a rarely documented endocyclic β‐hydride elimination of five‐membered metallacycles, which after reductive elimination gave rise to a Si−Rh I species that is capable of C−H activation.