Convenient routes to vinylideneruthenium dichlorides with basic and bulky tertiary phosphine ligands (PPri3 and PCy3)

Two synthetic routes to vinylideneruthenium complexes bearing basic and bulky tertiary phosphine ligands, RuCl2{=C=C(E)R}L-2 [L = PPr3i E = H, R = Ph (3a), t-Bu (3b), ferrocenyl (3c), p-MeO2CC6H4 (3d), p-MeOC6H4 (3e); L = PCy3, E = Il, R = Ph (4a), t-Bu (4b), ferrocenyl (4c); L = PPr3i, E = SiMe3, R = Ph (6), 1,1'-ferrocenediyl (7)], have been developed. Treatment of Ru(methallyl)(2)(cod) (1) with PPr3i and HCl (each 2 equiv) at -20 degrees C provides [RuCl2(PPr3i)(2)](n), which instantly reacts with phenylacetylene and tert-butylacetylene at room temperature to give 3a,b in isolated yields of 61 and 57%, respectively. On the other hand, heating a toluene solution of [RuCl2(p-cymene)](2) (2), phosphine (2 equiv/Ru), and alkyne (1 equiv/Ru) at 80 degrees C leads to the selective formation of the corresponding vinylidene complex. A variety of complexes (3a-e, 4a-c, 6, 7) are prepared from terminal alkynes and (trimethylsilyl)acetylene derivatives in 97-52% isolated yields. Treatment of 2 with PPr3i (2 equiv/Ru) and MeCN (10 equiv/Ru) in toluene gives RuCl2(PPr3i)(2)(NCMe)(2) (5) in 75% yield, which also serves as the precursor for vinylidene complexes; The X-ray crystal structures of 3a, 4a, and 5 are reported.