Preparation of Sn-, Ge-, and Si-heterocycles from zirconacycles

Stannacycles such as stannacyclopentanes, stannacyclopentenes and stanacyclopeneadienes were prepared from the corresponding zirconacycles. The effect: of addition of CuCl on the reaction of zirconacycles with tin halides is remarkable. In the case of germanium and silicon halides, the remarkable effect of CuCl addition was not observed. Symmetrical or unsymmetrical germa- and silacycles were prepared by the reaction of silicon or germanium halides with dilithio compounds prepared from the corresponding zirconacycles. Several heterocyclic compounds containing two metalloatoms were also prepared.