Interestingly, reaction with Me3SiOTf did not lead to decoordination of the ethynediolate ligand, contrary to the reactivity observed by Liddle and co-workers upon treatment of a related tris-amido U(IV) ethynediolate complex with a strong silyl electrophile (see In this previous study, the reaction with Me3SiI led to the silylation of the hydroxy groups and liberation of the ethynediolate fragment, which subsequently dimerized and rearranged into a spectroscopically identified furanone product. Indeed, acetylene diether compounds have been found to be stable at room temperature only in the presence of bulky substituents, 38 or h 2 -coordinated to transition metals. 16b The X-ray authenticated complex 7 unambiguously shows the formation of a similar furanone moiety in which the two trimethylsilyl groups are attached at the C4 position of the heterocycle rather than the O3 and O4 oxygen atoms, the latter remaining coordinated to metal center. The exploration of other functionalization agents to allow the liberation of the ethynediolate moiety is currently in progress. Scheme 5. Reported reactivity of a tris-amide U(IV) ethynediolate complex with Me3SiI. 17i