179117-06-7Relevant articles and documents
Zwitterionic iridium complexes with P,N-ligands as catalysts for the asymmetric hydrogenation of alkenes
Franzke, Axel,Pfaltz, Andreas
supporting information; experimental part, p. 4131 - 4144 (2011/06/21)
Several zwitterionic iridium complexes based on chiral P,N-ligands with imidazoline or oxazoline donors and anionic tetraarylborate or aryltrifluoroborate substituents have been synthesized. The corresponding cationic analogues have also been prepared, to evaluate the effect of the covalent linkage between the anion and the cationic metal complex in catalytic reactions. The respective pairs of structurally analogous precatalysts have been compared for their efficacies in the asymmetric hydrogenation of unfunctionalized olefins. In most cases, the anionic derivatization has virtually no influence on the asymmetric induction of the iridium complex. This is in accordance with X-ray structural studies, which have shown that the chiral environment of the cationic metal center is not affected by the anionic substituent. Depending on the nature of the counterion employed, the zwitterionic catalysts proved to be significantly more reactive than their cationic counterparts in nonpolar solvents. Copyright
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.