作者:Aditya L. Gottumukkala、Kiran Matcha、Martin Lutz、Johannes G. de Vries、Adriaan J. Minnaard
DOI:10.1002/chem.201200694
日期:2012.5.29
An efficient palladium catalyst is presented for the formation of benzylic quaternarystereocenters by conjugate addition of arylboronic acids to a variety of β,β‐disubstituted carbocyclic, heterocyclic, and acyclic enones. The catalyst is readily prepared from PdCl2, PhBOX, and AgSbF6, and provides products in up to 99 % enantiomeric excess, with good yields. Based on this strategy, (−)‐α‐cuparenone
Sodium Tetraarylborates as Effective Nucleophiles in Rhodium/Diene-Catalyzed 1,4-Addition to β,β-Disubstituted α,β-Unsaturated Ketones: Catalytic Asymmetric Construction of Quaternary Carbon Stereocenters
A rhodium-catalyzed1,4-addition of sodium tetraarylborates to beta,beta-disubstituted alpha,beta-unsaturated ketones is described. Highly efficient asymmetric catalysis has also been achieved by employing a readily available chiral diene ligand, leading to the construction of quaternary carbon stereocenters with high enantioselectivity.
Chiral Tetrafluorobenzobarrelenes as Effective Ligands for Rhodium-Catalyzed Asymmetric 1,4-Addition of Arylboroxines to β,β-Disubstituted α,β-Unsaturated Ketones
and Two Smoking Barrelenes: The rhodium‐catalyzed 1,4‐addition of readily available arylboronic acid anhydrides to simple β,β‐disubstituted α,β‐unsaturated ketones creates quaternary carbon stereocenters with high enantiomeric excesses using a chiraltetrafluorobenzobarreleneligand.
Rhodium-Catalyzed Asymmetric 1,4-Addition of Aryl Alanes to Trisubstituted Enones: Binap as an Effective Ligand in the Formation of Quaternary Stereocenters
All for one and 1,4‐all: Readily available arylalanes are used in the rhodium‐catalyzed asymmetric conjugate addition reaction with a variety of cyclic and acyclic enones. The enhanced reactivity of the system allows the use of the common binapligand for the generation of quaternary benzylic stereocenters in excellent enantioselectivity (see scheme).