AbstractAlthough the nucleophilicity/basicity at the phosphorus atom of the tetraphosphacubane2is reduced, apparently owing to the participation of the lone pairs of electrons in the P/C σ bonds, stepwise oxidation of the phosphorus atoms with bis(trimethylsilyl) peroxide or sulfur (in the presence of triethylamine) can be realized until all four phosphorus atoms have reacted to give products10–17. When2was treated with a large excess of selenium at 110°C, only the triselenide18was obtai