Organophosphorus Compounds, 114. Tetracyclic Phosphorus‐Aluminium‐Carbon Compounds – Synthesis by Cooligomerization of Kinetically Stabilized Phosphaalkynes with Trialkylaluminium Compounds

When the trialkylaluminium reagents 5 are allowed to react with phosphaalkynes 4 in n-pentane, a highly selective phosphaalkyne cyclotrimerization with incorporation of two organometallic units occurs ( 6). The tetracyclooctane derivatives 6a–e represent the first examples of phosphorus-aluminium-carbon cage compounds. The polycyclic products 6 are able to function as ligands in transition-metal complexes ( 7), which is illustrated by the reactions of 6b, c with nonacarbonyldiiron and pentacarbonyl(tetrahydrofuran)tungsten, respectively.