395664-08-1Relevant academic research and scientific papers
The application of intramolecular radical cyclizations of acylsilanes in the regiospecific formation of cyclic silyl enol ethers
Huang,Chang,Wang,Tsai
, p. 8983 - 8991 (2007/10/03)
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 between the same two carbon atoms. This approach is limited to the formation of five-membered rings. In another route, ω-bromo-α-phenylsulfonylacylsilanes are synthesized. The radical cyclizations of these α-sulfonylacylsilanes also give cyclic silyl enol ethers. The phenylsulfonyl moiety is the radical leaving group in this system. Furthermore, the newly formed σ-bond and π-bond are located at adjacent positions sharing a single carbon atom. The latter approach is effective for both five- and six-membered ring formation.
