Reduction of the dihalocyclopentasilanes. A quest for a homocyclic silylene.

The reduction of dichloro- and dibromo-cyclopentasilanes with C8K was investigated. A potassium silyl anion and a fused tricyclic silane were isolated, respectively. These results indicate that a homocyclic silylene intermediate is generated in the reduction of dibromocyclopentasilane. The trimethylsilyl group is bulky enough to protect the silylene from dimerization, however, it is not a good protecting group for hindering the 1,2-silyl migration.