Tungsten-Catalyzed Alkyne Metatheses in Transition-Metal Coordination Spheres:  Versatile New Syntheses of Metallamacrocycles

The title reaction (10−15 mol % of (t-BuO)₃W(⋮C-t-Bu), chlorobenzene, 80 °C) is applied to octahedral and square-planar 18- and 16-valence-electron rhenium, ruthenium, and platinum complexes with cis- or trans-Ph₂P(CH₂)₆C⋮CCH₃ ligands. NMR analyses show ca. 90−70% educt conversions, and 17-membered diphosphine chelates have been isolated in 59−47% yields and crystallographically characterized.