title: A new class of modular P,N-ligand library for asymmetric Pd-catalyzed allylic substitution reactions: a study of the key Pd-pi-allyl intermediates.
abstract: A new class of modular P,N-ligand library has been synthesized and screened in the Pd-catalyzed allylic substitution reactions of several substrate types. These series of ligands can be prepared efficiently from easily accessible hydroxyl-oxazole/thiazole derivatives. Their modular nature enables the bridge length, the substituents at the heterocyclic ring and in the alkyl backbone chain, the configuration of the ligand backbone, and the substituents/configurations in the biaryl phosphite moiety to be easily and systematically varied. By carefully selecting the ligand components, therefore, high regio- and enantioselectivities (ee values up to 96 %) and good activities are achieved in a broad range of mono-, di-, and trisubstituted linear hindered and unhindered substrates and cyclic substrates. The NMR spectroscopic and DFT studies on the Pd-pi-allyl intermediates provide a deeper understanding of the effect of ligand parameters on the origin of enantioselectivity.
authors: Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, C/Marcel líDomingo, s/n. 43007 Tarragona, Spain.
authors: Javier
authors: J
authors: Mazuela
authors: Alexander
authors: A
authors: Paptchikhine
authors: Päivi
authors: P
authors: Tolstoy
authors: Oscar
authors: O
authors: Pàmies
authors: Montserrat
authors: M
authors: Diéguez
authors: Pher G
authors: PG
authors: Andersson
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D008024:Ligands; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000498:Allyl Compounds; D008024:Ligands; D010165:Palladium