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, RuCl 2 { C C(E)R}L 2 [L = PPr i 3, E = H, R = Ph ( 3a ), t -Bu ( 3b ), ferrocenyl ( 3c ), p -MeO 2 CC 6 H 4 ( 3d ), p -MeOC 6 H 4 ( 3e ); L = PCy 3, E = H, R = Ph ( 4a ), t -Bu ( 4b ), ferrocenyl ( 4c ); L = PPr i 3, E = SiMe 3, R = Ph ( 6 ), 1,1‘-ferrocenediyl ( 7 )], have been developed. Treatment of Ru(methallyl) 2 (cod) ( 1 ) with PPr i 3 and HCl (each 2 equiv) at −20 °C provides [RuCl 2 (PPr i 3 ) 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 [RuCl 2 ( p -cymene)] 2 ( 2 ), phosphine (2 equiv/Ru), and alkyne (1 equiv/Ru) at 80 °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 PPr i 3 (2 equiv/Ru) and MeCN (10 equiv/Ru) in toluene gives RuCl 2 (PPr i 3 ) 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.