Chiral Bis(N-sulfonylamino)phosphine- and TADDOL-Phosphite-Oxazoline Ligands: Synthesis and Application in Asymmetric Catalysis
作者:Robert Hilgraf、Andreas Pfaltz
DOI:10.1002/adsc.200404168
日期:2005.1
has been prepared, containing a chiral oxazoline ring and as a second chiral unit a bis(N-sulfonylamino)phosphine group embedded in a diazaphospholidine ring or a cyclic phosphite group derived from TADDOL. These modular ligands are readily synthesized from chiral amino alcohols and chiral 1,2-diamines or TADDOLs. Palladium and iridium complexes derived from these ligands were found to be efficient catalysts
A new phosphoramiditeligand was used in the iridium-catalyzed allylicsubstitution reaction. This permitted high regio- and enantioselectivities on a wide variety of substrates and nucleophiles. Because of the stereospecificity of the reaction obtained by using branched substrates, a kinetic resolution reaction was attempted. The origin of the impressive efficiency of this ligand in terms of kinetics
Very Efficient Phosphoramidite Ligand for Asymmetric Iridium-Catalyzed Allylic Alkylation
作者:Alexandre Alexakis、Damien Polet
DOI:10.1021/ol048607y
日期:2004.9.1
[reaction: see text] Linear or branched allylic carbonates or acetates undergo enantioselective iridium-catalyzedallylic substitution with sodium malonate. The reaction is wide in scope and affords the branched product in high yield and with high regio- (up to >99:1) and enantioselectivity (up to 98%). Ten aromatic or aliphatic substrates were successfully tested.
TRANSFER OF ASYMMETRY BY THE PALLADIUM-CATALYZED ALKYLATION OF CHIRAL ALLYLIC SULFINATES
作者:Kunio Hiroi、Ryuichi Kitayama、Shuko Sato
DOI:10.1246/cl.1984.929
日期:1984.6.5
The palladium-catalyzed substitution of chiral allylic sulfinates was performed by the initial transformation of the sulfinates into allyl sulfones and the subsequent alkylation of the sulfones with retention of configuration. Reaction of trans- and cis-2-butenyl (S)-(−)-p-toluenesulfinate with the sodium salt of dimethyl malonate was undertaken in the presence of tetrakis(triphenylphosphine)palladium and triphenylphosphine to produce dimethyl (S)-(+)- and (R)-(−)-1-buten-3-ylmalonate, respectively, with the α-alkylated product, dimethyl 2-butenylmalonate.