Cyclotrimetallenes mixed

The reaction of the mixed cyclotrimetallenes 22 and 23 with phenylacetylene also proceeds through the initial [2 + 2] cycloaddition of the first molecule of phenylacetylene across the E=Si (E = Si, Ge) double bond with the formation of the three- and four-membered bicyclic compounds 30 and 3122. But the reaction does not stop at this stage valence isomerization of the bicyclic compound takes place to form the silole type structures 32 and 33 with one Si=C and one Ge=C double bond, which in turn... 

---