Application of P-Stereogenic Aminophosphine Phosphinite Ligands in Asymmetric Hydroformylation
作者:Regine Ewalds、Eva B. Eggeling、Alison C. Hewat、Paul C. J. Kamer、Piet W. N. M. van Leeuwen、Dieter Vogt
DOI:10.1002/(sici)1521-3765(20000417)6:8<1496::aid-chem1496>3.0.co;2-8
日期:2000.4.17
New chiral aminophosphine phosphinite ligands with a stereogenic center at the aminophosphine phosphorus atom were prepared based on (R,S)-ephedrine as the chiral auxiliary and backbone. Substituents at the chiral aminophosphine as well as at the phosphinite phosphorus atom were varied. These new ligands were applied to the rhodium-catalyzed asymmetric hydroformylation of vinyl arenes, The enantiomeric excess reached up to 77%. H-1 and P-31 NMR studies of the Rh complexes under syngas pressure reveal that [HRh(CO)(2)((PP)-P-boolean AND)] complexes with the NP* moiety in an axial position are responsible for enantioselectivity.