New cyclizations via catalytic ruthenium vinylidenes.

Paper based on a presentation at the 14th International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis (OMCOS-14), 2-6 August 2007, Nara, Japan. Other presentations are published in this issue, pp. 807-1194New carbocyclizations that proceed via catalytic metal-vinylidenes are presented. Metal-vinylidene catalytic species, which are easily accessible from terminal alkynes and catalytic amounts of transition-metal complexes, can be involved either in pericyclic reactions or in tandem processes triggered by nucleophilic attack at the electrophilic position of the vinylidene. In both cases, a wide variety of valuable cyclic compounds are easily accessible. Some recent carbocyclizations will be described. [ABSTRACT FROM AUTHOR]