Ru(CHPh)(H(2)IMes)(PCy3)Cl-2 (2) reacts with vinyl chloride to form Ru(CHCl)(H(2)IMes)(PCy3)Cl-2 (8) and styrene. Complex 8 is thermally unstable and decomposes rapidly to phosphoniocarbene complex Ru(CHPCy3)(H(2)IMes)Cl-3 and/or carbide complex Ru(C:)(H(2)IMes)(PCy3)Cl-2, depending on conditions. However, 8 can be observed at low temperature and can be trapped by alkyne, as shown by enyne metathesis of vinyl chloride with trimethylsilylacetylene. Vinyl bromide reacts similarly with 2.