Non-degenerate 1,2-silyl shift in silyl substituted alkyltrimethylcyclopentadienes

Activation parameters of non-degenerate 1,2-silyl shift between isomers b and a (for compounds 5-8) and between isomers b and c (for compounds 5 and 7) of new silyl substituted alkyltrimethylcyclopentadienes were evaluated from variable temperature NMR experiments. The reaction of 5 with strong dienophiles (DMAD, TCNE) led to different Diels-Alder products, which confirmed the isomers a and b.