Asymmetric 1,4-addition of arylboronic acids to α,β-unsaturated aldehydes proceeded in the presence of a rhodium catalyst (3 mol %) coordinated with a chiral diene ligand ((R,R)-Bn-bod*) to give the corresponding β-arylaldehydes with perfect 1,4-selectivity and with 88–97% enantioselectivity.
chiral Rh and Rh/Ag bimetallic nanoparticle catalysts consisting of polystyrene-based polymers with chiral diene moieties. The catalysts enable high-to-excellent yields and enantioselectivities to be obtained in asymmetric 1,4-addition reactions of arylboronic acids with α,β-unsaturated carbonyl compounds such as ketones, esters, and amides, and in other asymmetric reactions. The catalysts could be readily
Palladium and a simple chiral amine are used as co‐catalysts for the enantioselective conjugate addition of aryl boronic acids to α,β‐unsaturated aldehydes (see scheme). The synthetic utility of this co‐catalyzed reaction was demonstrated in the short total syntheses of (R)‐(−)‐curcumene and 4‐aryl‐2‐ones.
Chiral dihydrobenzo[1,4]oxazines as catalysts for the asymmetric transfer-hydrogenation of α,β-unsaturated aldehydes
作者:Christian Ebner、Andreas Pfaltz
DOI:10.1016/j.tet.2011.10.051
日期:2011.12
A new class of organocatalysts based on the structure of 2,3-dihydrobenzo[1,4]oxazine was prepared and applied in the enantioselective transfer-hydrogenation of α,β-unsaturatedaldehydes with Hantzsch ester as hydride donor. These catalysts proved to be particularly effective for the conjugate reduction of β,β-diaryl-substituted acrylaldehydes leading to saturated aldehydes bearing a stereogenic center
Asymmetric Synthesis of 3,3-Diarylpropanals with Chiral Diene−Rhodium Catalysts
作者:Jean-François Paquin、Christian Defieber、Corey R. J. Stephenson、Erick M. Carreira
DOI:10.1021/ja053270w
日期:2005.8.1
A general route to enantioenriched 3,3-diarylpropanals is presented. These useful building blocks are prepared via an asymmetric rhodium-catalyzed conjugate addition of arylboronic acids to cinnamaldehyde derivatives in the presence of chiral dienes. The addition of both electron-poor as well as electron-rich boronic acids proceeds smoothly with various enals in 63-90% yield with high enantioselectivities (89-93% ee).