title: Allenes as carbon nucleophiles in intramolecular attack on (pi-1,3-diene)palladium complexes: evidence for trans carbopalladation of the 1,3-diene.
abstract: Reaction of allene-substituted cyclohexa- and cyclohepta-1,3-dienes with [PdCl(2)(PhCN)(2)] gave eta(3)-(1,2,3)-cyclohexenyl- and eta(3)-(1,2,3)-cycloheptenylpalladium complexes, respectively, in which C-C bond formation between the allene and the 1,3-diene has occurred. Analysis of the (pi-allyl)palladium complexes by NMR spectroscopy, using reporter ligands, shows that the C-C bond formation has occurred by a trans carbopalladation involving nucleophilic attack by the middle carbon atom of the allene on a (pi-diene)palladium(II) complex. The stereochemistry of the (pi-allyl)palladium complexes was confirmed by benzoquinone-induced stereoselective transformations to allylic acetates.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden.
authors.forename: Ismet
authors.initials: I
authors.lastname: Dorange
authors.forename: Joakim
authors.initials: J
authors.lastname: Löfstedt
authors.forename: Katja
authors.initials: K
authors.lastname: Närhi
authors.forename: Johan
authors.initials: J
authors.lastname: Franzén
authors.forename: Jan-E
authors.initials: JE
authors.lastname: Bäckvall