π4s+ π2s cycloaddition of hexaphenylsilacyclopentadiene with ethyl acrylate gives rise to a bicyclosilaheptene derivative. High resolution NMR studies have shown that the ester group in this adduct is in the endo position and that the ester methylene protons are magnetically inequivalent. Similar cycloadditions of hexaphenylsilacyclopentadiene, 1, 1-dimethyl-2, 3, 4, 5-tetraphenylsilacyclopentadiene, 1-methyl-1, 2, 3, 4, 5-pentaphenylsilacyclopentadiene, ...
