Synthesis, structure, and reactions of octakis(1,1,2-trimethylpropyl)octagermacubane

Octathexyloctagermacubane (1, thexyl = 1,1,2-trimethylpropyl) was synthesized by the condensation of trichloro-thexylgermane with Mg/MgBr2, and structurally characterized by X-ray crystallography. As in the case of the thexyl-substituted octasilacubane, a ring-opening reaction followed by skeletal rearrangement of 1 took place with PCl5 to give endo, exo- and exo,exo-4,8-dichlorooctathexyltetracycloocthathexyltetracyclo[3.3.0.0(2,7).0(3.6)] octagermanes. Treatment of these dichlorides with sodium afforded octagermacubane 1.