Fine-tuning monophosphine ligands for enhanced enantioselectivity. Influence of chiral hemilabile pendant groups.
[reaction: see text] C(2)-Symmetric P-(2-X-aryl)-2,5-dialkylphospholanes (X = dioxolan-2-yl or dioxan-2-yl), designed on the basis of a working model for asymmetric induction, are effective ligands for the Ni(II)-catalyzed asymmetric hydrovinylation of styrenes. Excellent yields (>99%), selectivities for the desired 3-arylbutenes (>99%), high S/C ratios (>1200), and ee's (up to 91%) have been realized for a number of prototypical vinylarenes. In the dioxolane series, the selectivity depends on the configuration of the C(4) and C(5)() carbons.
Zhang
Aibin
A
Department of Chemistry, 100 West 18th Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
RajanBabu
T V
TV
D002384:Catalysis; D008024:Ligands; D008968:Molecular Conformation; D009532:Nickel / Q000737:chemistry; D010720:Phosphines / Q000138:chemical synthesis / Q000737:chemistry*; D013237:Stereoisomerism; D013343:Styrenes / Q000138:chemical synthesis*
D008024:Ligands; D010720:Phosphines; D013343:Styrenes; D009532:Nickel