Sila-spirocyclization involving unstrained C(sp³)-Si bond cleavage

C − Si Bond cleavage is one of the key elemental steps for a wide variety of silicon-based transformations. However, the cleavage of unstrained Si−C(sp³) bonds catalyzed by transition metal are still in their infancy. They generally involve the insertion of a M − C(sp²) species into the C − Si bond and consequent intramolecular C(sp²)‒Si coupling to exclusively produce siloles. Here we report the Pd-catalyzed sila-spirocyclization, in which the Si−C(sp³) bond is activated by the insertion of a M − C(sp³) species and followed by the formation of a new C(sp³)‒Si bond, allowing the construction of diverse spirosilacycles. This reactivity mode, which is strongly supported by DFT calculations may open an avenue for the Si−C(sp³) bond cleavage and silacycle synthesis.