The Cu‐free asymmetric allylic alkylation, catalysed by NHC, with Grignardreagents is reported on allyl bromide derivatives with good results. The enantioselectivity was quite homogeneous (around 85 % ee) on large and various substrates, regardless of the nature of the Grignardreagent. The formation of stereogenic quaternary centres was highly regioselective for both aliphatic and aromatic derivatives
Fine-Tuning Monophosphine Ligands for Enhanced Enantioselectivity. Influence of Chiral Hemilabile Pendant Groups
作者:Aibin Zhang、T. V. RajanBabu
DOI:10.1021/ol0495063
日期:2004.4.1
[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
Application of Supramolecular Bidentate Hybrid Ligands in Asymmetric Hydroformylation
作者:Rosalba Bellini、Joost N. H. Reek
DOI:10.1002/chem.201202044
日期:2012.10.15
which the phosphane ligand is in the axial position and the phosphoramidite adopts the equatorial position. These ligands were applied in the asymmetric Rh‐catalysed hydroformylation of styrene and para‐substituted analogues. In these hydroformylation reactions, modification of the electronic and steric properties of the zinc(II)‐templates appear to have a significant influence on the activity and
Palladium-catalyzed asymmetric hydrovinylation under mild conditions using monodentate chiral spiro phosphoramidite and phosphite ligands
作者:Wen-Jian Shi、Jian-Hua Xie、Qi-Lin Zhou
DOI:10.1016/j.tetasy.2004.12.017
日期:2005.2
catalysts in the asymmetrichydrovinylation of vinylarenes with ethylene. The hydrovinylation products were obtained in modest selectivity with enantioselectivities up to 92% ee. The structures of the palladium catalysts have been analyzed by X-ray diffraction. The active catalyst contained one monodentate ligand. A kinetic resolution accompanied the isomerization of the hydrovinylation product in the
Enantioselective hydrovinylation via asymmetric counteranion-directed ruthenium catalysis
作者:Gaoxi Jiang、Benjamin List
DOI:10.1039/c1cc12499d
日期:——
The first Ru-catalyzed enantioselective hydrovinylation has been realized by using an asymmetriccounteranion-directedcatalysis strategy. Styrene derivatives react with ethylene in excellent yields and promising enantioselectivity using this approach.