Formation of Ruthenaindenes by Cyclometalation of Ruthenium(II) Diarylbutenyne Complexes

The reaction of diarylbutenynylruthenium complexes [Ru(η3-C(CCC6H4R)C(R′)C6H4R)(PMe3)4]+ (C6H4R = C6H4-4-tBu, Ph, C6H4-4-Me; R′ = H, Me) with dimethylmagnesium yields the cyclometalated ruthenaindene complexes [Ru(C(CCC6H4R)C(R′)C6H3R)(PMe3)4] with ruthenium incorporated into the five-membered ring of an indene. The reaction involves the initial formation of methylruthenium complexes, which then rearrange with the elimination of methane to yield the product. The complexes [Ru(C(CCC6H4R)C(R′)C6H3R)(PMe3)4] (C6H4R = C6H4-4-tBu, R′ = H; C6H4R = Ph, R′ = Me) were crystallographically characterized.