Acylsilanes with terminal α-stannyl bromide or xanthate functionalities are prepared. α- Stannyl radicals generated from these acylsilanes undergo intramolecular cyclizations to give cyclic silyl enol ethers regiospecifically. The radical processes involve radical cyclization, Brook rearrangement, and β-fragmentation in sequence. A tributylstannyl group serves as the radical leaving group. The newly formed σ-bond and π-bond are located ...