化学
对映体
催化作用
非对映体
对映体过量
对映选择合成
有机化学
组合化学
立体化学
作者
Kōichi Mikami,Kohsuke Aikawa,Yukinori Yusa,Jonathan J. Jodry,Masahiro Yamanaka
出处
期刊:Synlett
[Georg Thieme Verlag KG]
日期:2002-01-01
卷期号: (10): 1561-1578
被引量:143
摘要
While non-racemic catalysts can generate non-racemic products with or without the non-linear relationship in enantiomeric excesses between catalysts and products, racemic catalysts inherently give only a racemic mixture of chiral products. Racemic catalysts can be enantioselectively evolved into highly activated catalysts by association with chiral activators. Asymmetric activation strategy can produce greater enantiomeric excess in the products, even when using a catalytic amount of chiral activator per chiral or racemic catalysts bearing atropisomeric (atropos: from Greek a meaning not, and tropos meaning turn) ligands, than the enantioselectivity attained by the enantiomerically pure catalyst on its own. Some recent applications of the asymmetric activation catalysis that employ not only atropos and racemic ligands but also tropos ligands without enantiomeric resolution are herein reported. The great success of the asymmetric catalysts with tropos ligands clearly illustrate that chirally rigid atropos ligands can be replaced by chirally flexible tropos ligands to give preferentially the thermodynamically favorable diastereomer of catalysts with higher chiral efficiency than does the minor isomer. The asymmetric activation concept now progress toward the use of racemic but tropos ligands rather than the use of atropos ones.
科研通智能强力驱动
Strongly Powered by AbleSci AI