title: Formation of osmium- and ruthenium-cyclobutylidene complexes by ring expansion of alkylidenecyclopropanes.
abstract: Alkylidenecyclopropanes containing a chelation assistant at the terminal carbon atom of the olefinic moiety undergo an Os- or Ru-promoted ring expansion reaction to afford metal cyclobutylidene derivatives. The process occurs through a novel mechanism that implies a 1,2-migration of a CH(2) group of the three-membered ring from an olefinic carbon atom to the other one. It takes place, without direct participation of the metal, on a metallaheterocyclopentene intermediate which is generated from an eta(2)-methylenecyclopropane species stabilized by coordination of the chelation assistant.
authors.affiliation: Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Castro-Rodrigo
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Esteruelas
authors.forename: Sara
authors.initials: S
authors.lastname: Fuertes
authors.forename: Ana M
authors.initials: AM
authors.lastname: López
authors.forename: Fernando
authors.initials: F
authors.lastname: López
authors.forename: José L
authors.initials: JL
authors.lastname: Mascareñas
authors.forename: Silvia
authors.initials: S
authors.lastname: Mozo
authors.forename: Enrique
authors.initials: E
authors.lastname: Oñate
authors.forename: Lucía
authors.initials: L
authors.lastname: Saya
authors.forename: Lara
authors.initials: L
authors.lastname: Villarino