Synthesis of new chiral hydroxy oxazolines and their use in the catalytic asymmetric phenyl transfer to aldehydes
摘要:
Starting either from benzoylformic acid or ethyl oxamate and enantiopure beta-amino alcohols, several chiral alpha-hydroxy oxazolines have been prepared by short synthetic routes. Subsequently, they have been employed in the catalytic asymmetric phenyl transfer to various aldehydes, using a mixture of triphenylborane and diethylzinc as the phenyl source. The corresponding secondary alcohols were obtained with good enantioselectivities (up to 81% ee) and up to 92% yield. (c) 2005 Elsevier Ltd. All rights reserved.
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
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.
Chiral Bis(<i>N</i>-tosylamino)phosphine- and TADDOL-Phosphite-Oxazolines as Ligands in Asymmetric Catalysis
作者:Robert Hilgraf、Andreas Pfaltz
DOI:10.1055/s-1999-2939
日期:1999.11
A series of P,N-ligands containing a chiral oxazoline ring and a chiral bis(N-tosylamino)phosphine group derived from a 1,2-diamine or a chiral cyclic phosphite group derived from TADDOL has been prepared. These compounds proved to be efficient ligands for enantiocontrol of palladium-catalyzed allylic alkylations and iridium-catalyzed hydrogenations of olefins.
SimplePHOX, a Readily Available Chiral Ligand System for Iridium-Catalyzed Asymmetric Hydrogenation
作者:Sebastian P. Smidt、Frederik Menges、Andreas Pfaltz
DOI:10.1021/ol049235w
日期:2004.6.1
[reaction: see text] New Ir-SimplePHOX complexes Ir-6-Ir-9 catalyze the quantitative, highlyenantioselective hydrogenation of a range of unfunctionalized and functionalized olefins. Synthesis, catalytic results, and X-ray crystal structures are presented here.
Chiral Bis(<i>N</i>-arylamino)phosphine-oxazolines: Synthesis and Application in Asymmetric Catalysis
作者:Marc Schönleber、Robert Hilgraf、Andreas Pfaltz
DOI:10.1002/adsc.200800221
日期:2008.9.5
N-alkylation of chiral 1,2-diamines followed by ring closure with phosphorus trichloride (PCl3) and subsequent coupling with an oxazoline alcohol resulted in a new class of N,Pligands. The corresponding iridium tetrakis[3,5-bis(trifluormethyl)phenyl]borate (BArF) complexes were found to be efficient catalysts for the enantioselectivehydrogenation of unfunctionalized olefins and α,β-unsaturated carboxylic