201409-47-4Relevant academic research and scientific papers
Chiral phosphinooxazolines with a Bi- or tricyclic oxazoline moiety - Applications in Pd-catalyzed allylic alkylations
Wiese, Burkhard,Helmchen, Guenter
, p. 5727 - 5730 (1998)
Phosphinooxazolines with a bi- or tricyclic oxazoline moiety are described. In Pd-catalyzed alkylations of 1,3-dimethylallyl acetate with sodium dimethyl malonate enantiomeric excess of up to 89.5 % was obtained. This is the best result so far achieved for this substrate with P,N-chelate ligands.
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.
