Coupling Reactions of Terminal Acetylenes with a Cyclometalated Aryl Ligand

Reaction of RuCl 2 (PPh 3 ) 3 with 1,3-(PPh 2 CH 2 ) 2 C 6 H 4 in refluxing 2-propanol produced RuCl(PPh 3 )(PCP) (PCP = 2,6-(PPh 2 CH 2 ) 2 C 6 H 3 ). Reaction of RuCl(PPh 3 )(PCP) with PhC⋮CH gave the unusual coupling product RuCl(PPh 3 ){η 4 -CHPh C-2,6-(PPh 2 CH 2 ) 2 C 6 H 3 }, which has been characterized by X-ray diffraction. Coupling also occurred between RuCl(PPh 3 )(PCP) and HC⋮CC(OH)(Ph)CH 3 to give RuCl(PPh 3 ){η 4 -CH 2 CPhCH C-2,6-(PPh 2 CH 2 ) 2 C 6 H 3 }.