improved generation of chiral cationic iridium catalysts for the asymmetricisomerization of primaryallylicalcohols is disclosed. The design of these air‐stable complexes relied on the preliminary mechanistic information available, and on Charton analyses using two preceding generations of iridium catalysts developed for this highly challenging transformation. Sterically unbiased chiral aldehydes
Expanded scope for the iridium-catalyzed asymmetric isomerization of primary allylic alcohols using readily accessible second-generation catalysts
作者:Luca Mantilli、Clément Mazet
DOI:10.1039/b920342g
日期:——
A second generation of chiral (P,N)-iridium catalysts--readily accessible from inexpensive L-serine--displays expanded scope for the asymmetricisomerization of primaryallylicalcohols.
作者:Stéphane G. Ouellet、Jamison B. Tuttle、David W. C. MacMillan
DOI:10.1021/ja043834g
日期:2005.1.1
The first enantioselectiveorganocatalytic hydride reduction has been accomplished. The use of iminium catalysis has provided a new organocatalytic strategy for the enantioselectivereduction of beta,beta-substituted alpha,beta-unsaturated aldehydes to generate beta-stereogenic aldehydes. The use of imidazolidinone 2 as the asymmetric catalyst has been found to mediate the transfer of hydrogen to a
第一次对映选择性有机催化氢化物还原已经完成。亚胺催化剂的使用为β,β-取代的α,β-不饱和醛的对映选择性还原生成β-立体醛提供了一种新的有机催化策略。已发现使用咪唑烷酮 2 作为不对称催化剂可介导氢从 Hantzsch 乙酯到一大类烯醛底物的转移。催化剂 2 在选择性 E-烯烃还原之前加速 EZ 异构化的能力允许在这个操作简单的协议中实施几何不纯的烯醛。
Access to High Levels of Molecular Complexity by One-Pot Iridium/Enamine Asymmetric Catalysis
Independent workers with team spirit: A catalytic sequence that exploits the compatibility of (chiral) cationic iridium catalysts for the isomerization of primary allylic alcohols to aldehydes with organocatalysts has been developed for the highly enantioselective α functionalization of aldehydes (see scheme: up to 66 % yield, d.r. 49:1, 99 % ee). The reaction displayed useful generality with respect