title: Modular bis(oxazoline) ligands for palladium catalyzed allylic alkylation: unprecedented conformational behaviour of a bis(oxazoline) palladium eta3-1,3-diphenylallyl complex.
abstract: New families of enantiopure bis(oxazolines) with 4,5-trans (5 a-g) or 4,5-cis (6 c) stereochemistry at the individual rings have been prepared in high yield. Their eta(3)-allyl palladium complexes (8 a-g, 9 c and 10) have been used as catalytic precursors in allylic alkylation reactions with excellent enantioselectivities (up to 96 %) for the trans oxazoline derivatives, while Pd/6 c system was inactive. NMR studies on palladium eta(3)-1,3-diphenylallyl intermediates (11 a, c and e) showed the presence of syn/syn- and syn/anti-allyl isomers in solution; this resembles the first example of eta(3)-eta(1)-eta(3) isomerism in Pd allylic complexes containing bis(oxazolines) derived from malonic acid.
authors.affiliation: Departament de Química Orgànica, Universitat de Barcelona Parc Científic de Barcelona, Josep Samitier 1-5 08028 Barcelona, Spain.
authors.forename: Miquel Angel
authors.initials: MA
authors.lastname: Pericàs
authors.forename: Cristina
authors.initials: C
authors.lastname: Puigjaner
authors.forename: Antoni
authors.initials: A
authors.lastname: Riera
authors.forename: Anton
authors.initials: A
authors.lastname: Vidal-Ferran
authors.forename: Montserrat
authors.initials: M
authors.lastname: Gómez
authors.forename: Francisco
authors.initials: F
authors.lastname: Jiménez
authors.forename: Guillermo
authors.initials: G
authors.lastname: Muller
authors.forename: Mercè
authors.initials: M
authors.lastname: Rocamora