palladium-catalyzed allylicsubstitutions of a wide range of substrate types and nucleophiles using a bidentate ligand composed of oxazoline and chirally flexible biaryl phosphite elements. This unusually wide substrate scope is shown by experimental and theoretical studies of its η3-allyl and η2-olefin complexes not to be a result of configurational interconversion of the biaryl unit, since the ligand
The regioselectivity in the ruthenium-catalysed allylicalkylation of mono substituted allyl acetates with the malonate anion was highly controlled by Ru3(CO)12 with 2-(diphenylphosphino)benzoic acid, and the linear-type alkylated product was obtained.
Bis(perfluoroalkyl) Phosphino-Oxazoline: A Modular, Stable, Strongly π-Accepting Ligand for Asymmetric Catalysis
作者:Zongjian Hu、Yuguang Li、Kai Liu、Qilong Shen
DOI:10.1021/jo3011717
日期:2012.9.21
A new class of stable, strongly π-accepting and modular bis(perfluoroalkyl)-phosphine-oxazoline ligands (FOX) as CO mimics was prepared. It was demonstrated that these ligands, when coordinated to palladium catalysts, promote the asymmetric alkylation of monosubstituted allyl substrates with excellent regio- and enantioselectivity. Solid and solution structure analysis of the FOX-ligated Pd-allyl intermediate
In the RuCl2(p-cymene)/PPh3 catalysed regioselective allylicalkylation of monosubstituted allyl acetates with malonate anion, the selective substitution at the position originally substituted with acetate was observed.
The branched, chiral products 1 are formed preferentially in the allylicalkylations in Equation (1) when the Pd catalyst contains the P,N ligand L* or derivatives thereof. The ligands are readily synthesized from commercially available precursors.