title: Promotion of selective pathways in isomerizing functionalization of plant oils by rigid framework substituents.
abstract: The 1,2-(CH2 P(1-adamantyl)2 )2 C6 H4 (dadpx) coordinated palladium complex [(dadpx)Pd(OTf)2 ] (1) is a catalyst precursor for the isomerizing methoxycarbonylation of the internal double bond of methyl oleate, with an unprecedented selectivity (96 %) for the linear diester 1,19-dimethyl nonadecanedioate. Rapid formation of the catalytically active solvent-coordinated hydride species [(dadpx)PdH(MeOH)](+) (3-MeOH) is evidenced by NMR spectroscopy, and further isolation and X-ray crystal structure analysis of [(dadpx)PdH(PPh3 )](+) (3-PPh3 ). DFT calculations of key steps of the catalytic cycle unravel methanolysis as the decisive step for enhanced selectivity and the influence of the rigid adamantyl framework on this step by destabilization of transition states of unselective pathways.
authors.affiliation: Department of Chemistry, University of Konstanz, 78464 Konstanz (Germany), Fax: (+49) 7531-88-5152.
authors.forename: Josefine T
authors.initials: JT
authors.lastname: Christl
authors.forename: Philipp
authors.initials: P
authors.lastname: Roesle
authors.forename: Florian
authors.initials: F
authors.lastname: Stempfle
authors.forename: Gerhard
authors.initials: G
authors.lastname: Müller
authors.forename: Lucia
authors.initials: L
authors.lastname: Caporaso
authors.forename: Luigi
authors.initials: L
authors.lastname: Cavallo
authors.forename: Stefan
authors.initials: S
authors.lastname: Mecking
mesh_terms: D018360:Crystallography, X-Ray; D007536:Isomerism; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D010938:Plant Oils
keywords: carbonylation; catalysis; isomerization; renewable resources; selectivity