Enantioselective Catalytic Conjugate Addition of Dialkylzinc Reagents using Copper–Phosphoramidite Complexes; Ligand Variation and Non-linear Effects
作者:Leggy A Arnold、Rosalinde Imbos、Alessandro Mandoli、André H.M de Vries、Robert Naasz、Ben L Feringa
DOI:10.1016/s0040-4020(00)00142-3
日期:2000.4
cyclohexenone and chalcone in order to assess the structural features that are important for stereocontrol. A sterically demanding amine moiety is essential to reach high e.e.’s. Enantioselectivities for chalcones up to 89% and for cyclic enones up to 98% were found. Studies on non-linear effects with the best ligands for both cyclohexenone and chalcone showed clear non-linear effects for both cyclic
Switchable Stereoselectivity: The Effects of Substituents on the D2-Symmetric Biphenyl Backbone of Phosphoramidites in Copper-Catalyzed Asymmetric Conjugate Addition Reactions with Triethylaluminium
A highly enantioselective copper‐catalyzed conjugateaddition with triethylaluminium was developed using phosphoramidite ligands bearing a D2‐symmetric biphenylbackbone. For these ligands we demonstrated that the 3,3′,5,5′‐substituents on the biphenylbackbone can completely reverse the absolute configuration of the products.
Multinuclear Cu/Zn complex-catalyzed efficient asymmetric conjugateaddition of organozincreagents to acyclic and cyclic enones has been developed in the presence of a wide variety of regioisomeric chiral diols bearing phosphorus moieties as ligands. The regioisomeric SPINOL-PHOS ligands based on a SPINOL architecture showed an unexpected inversion of stereoselectivity.
Multinuclear Catalyst for Copper-Catalyzed Asymmetric Conjugate Addition of Organozinc Reagents
作者:Kohei Endo、Mika Ogawa、Takanori Shibata
DOI:10.1002/anie.200906839
日期:2010.3.22
A whole lot o' metal: An efficient copper‐catalyzed asymmetric conjugate addition was achieved using a binol‐derived ligand. The catalytic system has a turnover number of 2000, and the excellent catalytic performance could be attributed to the generation of a multinuclear complex such as 1. binol=2,2′‐dihydroxy‐1,1′‐binaphthyl.
Newly designed phosphino-phenol 1c was found to be an efficient chiral auxiliary for copper-mediated asymmetric conjugate addition of diethylzinc to acyclicenones. High enantioselectivity up to >99% ee was achieved in the reaction of acyclic α,β-enones.