Tetrameric and Dodecameric tert‐Butylethynyllithium; A Novel Aggregation Principle in Organolithium Compounds

The structures of the title compounds are cubane-like owing to stacking of cyclic R2Li2 structural units. This structural principle is not limited to the title compounds [R2Li2]2 and [R2Li]6 1. It should be possible to form other oligomers [R2Li2]n, n≥3, the four terminal Li atoms of which can accommodate solvent molecules.