64028-98-4Relevant academic research and scientific papers
β-Alkoxy- and β-Hydroxyalkylphosphanes as Ligands in the Stereoselective Hydrogenation - A Comparison
Boerner, Armin,Kless, Achim,Kempe, Rhett,Heller, Detlef,Holz, Jens,Baumann, Wolfgang
, p. 767 - 774 (2007/10/02)
Optically pure 1,4-bis(diphenylphosphanyl)-2-hydroxy-butane (2) and its methyl ether 1 can be conveniently prepared by starting from chiral pool substances such as malic or L-ascorbic acid.Different pathways to these compounds were elucidated.In one case an interesting migration of an acetalic OH-protective group was observed.The reaction of the bisphosphenes with Rh(I) or Pd(II) gave uniform metal complexes.On the basis of X-ray structural analysis, NMR and IR data it was concluded that in the investigated precatalysts of the type BF4 a coordination of the alkoxy or hydroxy oxygen to the metal does not take place .Nevertheless, significant differences in enantioselectivity and activity could be observed when several prochiral substrates were hydrogenated. - Keywords: Ether phosphanes / Hydroxyalkylphosphanes / Rhodium / Asymmetric hydrogenation
