title: Reactions of diazo compounds with alkenes catalysed by [RuCl(cod)(Cp)]: effect of the substituents in the formation of cyclopropanation or metathesis products.
abstract: The reaction of diazo compounds with alkenes catalysed by complex [RuCl(cod)(Cp)] (cod = 1,5-cyclooctadiene, Cp = cyclopentadienyl) has been studied. The catalytic cycle involves in the first step the decomposition of the diazo derivative to afford the reactive [RuCl(Cp){=C(R(1))R(2)}] intermediate and a mechanism is proposed for this step based on a kinetic study of the simple coupling reaction of ethyl diazoacetate. The evolution of the Ru-carbene intermediate in the presence of alkenes depends on the nature of the substituents at both the diazo N(2)=C(R(1))R(2) (R(1), R(2) = Ph, H; Ph, CO(2)Me; Ph, Ph; C(R(1))R(2) = fluorene) and the olefin substrates R(3)(H)C=C(H)R(4) (R(3), R(4) = CO(2)Et, CO(2)Et; Ph, Ph; Ph, Me; Ph, H; Me, Br; Me, CN; Ph, CN; H, CN; CN, CN). A remarkable reactivity of the complex was recorded, especially towards unstable aryldiazo compounds and electron-poor olefins. The results obtained indicate that either cyclopropanation or metathesis products can be formed: the first products are favoured by the presence of a cyano substituent at the double bond and the second ones by a phenyl.
authors.affiliation: Dipartimento di Scienze Chimiche, Università degli Studi di Padova via Marzolo 1, 35131 Padova, Italy. marino.basato@unipd.it
authors.forename: Marino
authors.initials: M
authors.lastname: Basato
authors.forename: Cristina
authors.initials: C
authors.lastname: Tubaro
authors.forename: Andrea
authors.initials: A
authors.lastname: Biffis
authors.forename: Marco
authors.initials: M
authors.lastname: Bonato
authors.forename: Gabriella
authors.initials: G
authors.lastname: Buscemi
authors.forename: Filippo
authors.initials: F
authors.lastname: Lighezzolo
authors.forename: Pamela
authors.initials: P
authors.lastname: Lunardi
authors.forename: Chiara
authors.initials: C
authors.lastname: Vianini
authors.forename: Franco
authors.initials: F
authors.lastname: Benetollo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Del Zotto