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
2010 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, no 2, 620-638 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2010. Vol. 16, no 2, 620-638 p.
Allylic substitution, Asymmetric catalysis, Ligand design, N.P ligands, Palladium
IdentifiersURN: urn:nbn:se:uu:diva-121861DOI: 10.1002/chem.200901842ISI: 000274265100030PubMedID: 19937621OAI: oai:DiVA.org:uu-121861DiVA: diva2:306885