Asymmetric synthesis of optically active β-substituted ketones by highly enantioselective catalytic conjugate addition of dialkylzinc reagents to enones using a catalyst system of nickel(<scp>II</scp>)-chiral ligand–achiral ligand in acetonitrile/toluene
作者:Kenso Soai、Tomoiki Hayasaka、Shoji Ugajin
DOI:10.1039/c39890000516
日期:——
Highly enantioselective conjugate addition of dialkylzincreagents to aryl substituted enones using Ni(II)-bipyridyl–chiral ligand in acetonitrile (MeCN)/toluene as an in situ prepared catalyst system affords β-substituted ketones in up to 90% enantiomeric excess (e.e.).
The development of new ligands for catalytic asymmetric C-C bond formation is of great interest to organic synthesis. We describe here a new class of chiral phosphoramidites that embody one or two binaphthol units attached to an achiral azabicyclic [3.3.1] or [3.3.0] framework. These ligands were easily accessible from (R)1,1'-binaphthyl-2,2'-dioxaphosphorchloridite (4) and the corresponding heterobicyclic
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.
Remarkable Effect of Silyl Groups on Asymmetric Induction in a Conjugate Addition Reaction with <i>O</i>-Methylnorephedrine-Based<i> N</i>-Silylamidocuprates
作者:Steven H. Bertz、Craig A. Ogle、Abhinav Rastogi
DOI:10.1021/ja0455805
日期:2005.2.1
with chalcone, a classic substrate for studies of organocuprate conjugateaddition. For example, the butyl N-diphenylmethylsilylamidocuprate (T = Bu) affords a 99.2% ee (99% yield) of (S)-3-butyl-1,3-diphenyl-1-propanone. The remarkably high yields with this and other silyl ligands are attributed to the extraordinary activating effect of a beta-silicon atom on organocuprate reactions. The high ee is
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.