224564-59-4Relevant articles and documents
Studies on a Chiral (N,P) Ligand Containing a C2-Symmetric Aziridine Unit
Tanner, David,Wyatt, Paul,Johansson, Fredrik,Bertilsson, Sophie K.,Andersson, Pher G.
, p. 263 - 268 (2007/10/03)
As part of a program on the use of chiral aziridines in asymmetric synthesis and catalysis, the enantiopure (N,P) ligand 1, consisting of a C2-symmetric chiral aziridine and a triarylphosphine unit, was prepared. The synthesis was convergent and efficient, proceeding in five steps and 37% overall yield from 2-bromotoluene. The ligand was designed (a) for a study of the asymmetric Pd-catalyzed allylic substitution reaction, (b) in an attempt to obtain a measure of the trans effect of phosphorus relative to an aziridine nitrogen, and (c) to compare its performance with the corresponding chiral phosphinooxazoline species (computational studies having indicated certain similarities between the two ligand types). However, the new aziridine species did not provide levels of enantioselectivity comparable to those obtained with the phosphinooxazoline analogs, and our results serve to underline once more the difficulties associated with the rational design of ligands for asymmetric catalysis.
