Diastereoselective [2+2] Cyclizations
M. B. Boxer, H. Yamamoto*
University of Chicago, USA
21 September 2005 (online)
Diastereoselective [2+2] cyclization using aldehyde-derived silyl enol ethers and acrylates has been described. Many silyl groups were explored but the Si-Si bond present in the tris(trimethylsilyl)silyl group was essential for the reaction to succeed. TBS and TIPS did not give any product. The observed reactivity with TTMSS is attributed to its strong electron-donating properties and large steric size which stabilizes the cationic intermediate.