Phenylacetylene and its derivatives react with Cp*Ru(COD)CI under formation
of the neutral 2,5-bis-substituted dicarbene ruthenacycles chloro-Cp*ruthe
nacyclopenta-1,3,5-trienes (1a R = phenyl, 1b R = p-bromophenyl). Nucleophi
lic attack of PMe3 or P(OMe)(3) occurs at one cc-atom of the ruthenacyclope
ntatrienes 1 and leads under metal-chlorine bond cleavage to the correspond
ing Cp*Ru-allylcarbene complexes 2. The X-ray structures and spectroscopic
data of the complexes confirm the results. (C) 2001 Elsevier Science B.V. A
ll rights reserved.