The First Synthesis of the Sterically Encumbered Adamantoid Phosphazane P4(NtBu)6: Enabled by Mechanochemistry

All reported attempts to synthesize the tert-butyl-substituted adamantoid phosph(III)azane P-4((NBu)-Bu-t)(6) have failed, leading to the classification of this molecule as inaccessible and a literature example of steric control in chemistry of phosphorus-nitrogen compounds. We now demonstrate that this structure is readily accessible by a solvent-free mechanochemical milling approach, highlighting the importance of mechanochemical reaction environments in evaluating chemical reactivity.