150255-49-5Relevant academic research and scientific papers
In situ enzymatic screening (ISES) of P,N-ligands for Ni(0)-mediated asymmetric intramolecular allylic amination
Berkowitz, David B.,Shen, Weijun,Maiti, Gourhari
, p. 2845 - 2851 (2007/10/03)
An in situ enzymatic screening (ISES) approach to rapid catalyst evaluation recently pointed to Ni(0) as a new candidate transition metal for intramolecular allylic amination. This led to further exploration of chiral bidentate phosphine ligands for such transformations. Herein, a variety of P,N-ligands are examined for this Ni(0)-chemistry, using a model reaction leading into the vinylglycinol scaffold. On the one hand, an N,N-bis(2-diphenylphosphinoethyl)alkylamine ('PNP') ligand proved to be the fastest ligand yet seen for this Ni(0)-transformation. On the other, phosphinooxazoline (PHOX) ligands of the Pfaltz-Helmchen-Williams variety gave the highest enantioselectivities (up to 51% ee) among P,N-ligands examined.
Preparation of chiral phosphorus, sulfur and selenium containing 2-aryloxazolines
Peer, Markus,De Jong, Johannes C.,Kiefer, Matthias,Langer, Thomas,Rieck, Heiko,Schell, Heico,Sennhenn, Peter,Sprinz, Juergen,Steinhagen, Henning,Wiese, Burkhard,Helmchen, Guenter
, p. 7547 - 7583 (2007/10/03)
A series of enantiomerically pure 2-[2-(diarylphosphino)aryl]-oxazolines was prepared from commercially available or synthetic amino alcohols. For oxazoline formation three procedures were employed: (i) one pot condensation with a 2-halobenzoic acid (ii) ZnCl2 catalyzed condensation with a 2-halobenzonitrile, and (iii) a three step sequence via a 2-halobenzamide and a tosylate or chloride. Phosphinooxazolines containing stereogenic phosphorous were prepared by either diastereoselective nucleophilic substitution of halogenide of Ar1Ar2PCl or by nucleophilic aromatic substitution with LiPAr1Ar2. In addition, sulfur and selenium analogs were prepared.
Palladium-catalysed Asymmetric Allylic Substitution: a Ligand Design Incorporating Steric and Electronic Effects
Allen, Joanne V.,Coote, Steven J.,Dawson, Graham J.,Frost, Christopher G.,Martin, Christopher J.,Williams, Jonathon, M.
, p. 2065 - 2072 (2007/10/02)
Enantiomerically pure ligands containing a 4,5-dihydrooxazole moiety tethered to an auxiliary sulfur or phosphorus donor have been prepared.These ligands have been exploited for palladium-catalysed asymmetric allylic substitution, providing enantioselectivity in the catalytic reaction is discussed in terms of the steric and electronic influences provided by the ligand.
Preparation of Novel Sulfur and Phosphorus Containing Oxazolines as Ligands for Asymmetric Catalysis
Allen, Joanne V.,Dawson, Graham J.,Frost, Christopher G.,Williams, Jonathan M. J.,Coote, Steven J.
, p. 799 - 808 (2007/10/02)
The preparation of enantiomerically pure ligands which contain both an oxazoline group and an additional sulfur or phosphorus donor atom are described.Methylthiomethyl, o-thioanisyl and thienyl oxazolines have been prepared in one step, and o-diphenylphosphinophenyl oxazolines have been prepared in two steps in good yields from commercially available starting materials.
Asymmetric Palladium Catalysed Allylic Substitution Using Phosphorus Containing Oxazoline Ligands
Dawson, Graham J.,Frost, Christopher G.,Williams, Jonathan M. J.,Coote, Steven J.
, p. 3149 - 3150 (2007/10/02)
A series of new phosphorus-containing oxazoline ligands has been developed.The use of these ligands for asymmetric palladium catalysed allylic substitution of 1,3-diphenylprop-2-enyl-1-acetate 12 with the sodium salt of dimethylmalonate has been achieved
