Polyphospha.

The Eglinton reaction of diethynyl(2,4,6-tri-tert-butylphenyl)phosphane (7a), that is, the oxidative coupling of 3, 4, 5, or 6 of these phosphane units, affords a mixture of the 15-, 20-, 25-, and 30-membered macrocycles 8, 9, 10, and 11. Pure triphosphacyclopentadecahexayne 8 and pentaphosphacyclopentacosadecayne 10 were isolated by HPLC, while the mixture of 9 and 11 could not be separated. Multistep syntheses of open-chain polyphosphapolyynes are described, whose intra- or intermolecular coupling yields the phosphamacrocycles 8, 9, and 11.