Synthesis and applications to asymmetric catalysis of a series of mono- and bis(diazaphospholidine) ligands
作者:Donald Smyth、Heather Tye、Colin Eldred、Nathaniel W. Alcock、Martin Wills
DOI:10.1039/b106399p
日期:2001.11.1
The synthesis of a series of closely related mono- and bis(diazaphospholidine) ligands has been achieved using the condensation of a diamine with a bis(dimethylamino)arylphosphine. The resulting ligands have given excellent results in palladium-catalysed allylic substitution reactions to form C–C bonds (up to 89% ee) and C–N bonds (up to 78% ee).
chiral super Brønsted C–H acids, BINOL-derived phosphoryl bis((trifluoromethyl)sulfonyl) methanes (BPTMs), were developed. As compared to widely utilized BINOL-derived chiral phosphoric acids (BPAs) and N-triflyl phosphoramides (NTPAs), BPTMs displayed much higher Brønsted acidity, resulting in dramatically improved activity and excellent enantioselectivity as demonstrated in catalytic asymmetric Mukaiyama–Mannich
Ferrocenyl-QUINAP: a planar chiral P,N-ligand for palladium-catalyzed allylic substitution reactions
作者:Ralf J. Kloetzing、Paul Knochel
DOI:10.1016/j.tetasy.2005.12.001
日期:2006.1
The new planar chiral P,N-ligands 1a and 1b were prepared via a straightforward enantioselective synthesis using a Negishi cross-coupling and a sulfoxide/lithium exchange. Ligand 1a was successfully applied to Pd-catalyzed allylic alkylation (86% ee) and amination (83% ee) reactions.
This paper describes an enantioselective intermolecular allylicaminationcatalyzed by a chiral Brønsted acid via a possible chiral contact ion pair intermediate. A variety of symmetrical or unsymmetrical allylic alcohols can be smoothly aminated to afford the desired products in moderate to high yields with good enantioselectivities and/or regioselectivities.
Palladium-catalysed asymmetric allylic substitution: synthesis of α- and β-amino acids
作者:Justin F. Bower、Roshan Jumnah、Andrew C. Williams、Jonathan M. J. Williams
DOI:10.1039/a606586d
日期:——
Methodology has been established for the formation of
enantiomerically enriched α-amino acids using palladium-catalysed
allylic amination. The formation of enantiomerically enriched
allylamines has been achieved with high enantioselectivity. Oxidative
cleavage of the allylamines provides arylglycine and glutamic acid
derivatives. Additionally, enantiomerically enriched β-amino acids
have been prepared in high enantiomeric excess. Palladium-catalysed
asymmetric allylic substitution is used as the key synthetic
transformation.