Copper-Free Asymmetric Allylic Alkylation with Grignard Reagents
作者:Olivier Jackowski、Alexandre Alexakis
DOI:10.1002/anie.201000577
日期:2010.4.26
Open wide and say AAA: The copper‐free asymmetric allylicalkylation reaction of Grignardreagents, catalyzed by N‐heterocyclic carbenes, is reported for allyl bromide derivatives. This reaction offers good enantioselectivity and good to excellent γ regioselectivity, particularly for the formation of quaternary chiral centers (see scheme; Mes=mesityl).
张开嘴说AAA:据报道,N-杂环卡宾催化了格氏试剂的无铜不对称烯丙基烷基化反应,是烯丙基溴衍生物的反应。该反应提供了良好的对映选择性和良好的至优异的γ区域选择性,特别是对于形成四元手性中心(参见方案; Mes =甲磺酰基)。
ProPhenol Derived Ligands to Simultaneously Coordinate a Main‐Group Metal and a Transition Metal: Application to a Zn−Cu Catalyzed Reaction
作者:Barry M. Trost、Guoting Zhang、Minghao Xu、Xiaotian Qi
DOI:10.1002/chem.202104268
日期:2022.2.16
A new bi-functional ligandbearingchiralN-heterocycliccarbene (NHC) and prolinol moieties is designed and applied in the generation of a Cu/Zn hetero-bimetallic complex, which unlocks the asymmetric allylic alkylation reactions of allyl phosphates with zinc keto-homoenolates generated from cyclopropanols, leading to the formation of various γ-vinyl ketones with good regio- and enantio-selectivity
设计了一种新的带有手性 N-杂环卡宾(NHC) 和脯氨醇部分的双功能配体,并应用于生成 Cu/Zn 杂双金属配合物,从而解锁了磷酸烯丙酯与酮基高烯醇锌的不对称烯丙基烷基化反应由环丙醇生成,导致形成具有良好区域选择性和对映选择性的各种 γ-乙烯基酮。DFT 计算支持烯丙基磷酸酯与催化剂的螯合促进了 S N 2' 的添加,并且配体-底物空间相互作用解释了立体选择性结果。
Copper-Free Asymmetric Allylic Alkylation with a Grignard Reagent: Design of the Ligand and Mechanistic Studies
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
Enantioselective C2–H Alkylation of Pyridines with 1,3-Dienes via Ni–Al Bimetallic Catalysis
作者:Jiang-Fei Li、Deng Pan、Hao-Rui Wang、Tao Zhang、Yi Li、Genping Huang、Mengchun Ye
DOI:10.1021/jacs.2c09306
日期:2022.10.19
A chiral phosphine oxide-ligated Ni–Al bimetallic catalyst was used to realize an enantioselective C2–H alkylation of pyridines without the need of a C2-block. A wide range of pyridines, including unsubstituted pyridine, C3, C4, and C2-substituted pyridines, and even complex pyridine-containing bioactive molecules are well compatible with the reaction, providing up to 81% yield and up to 97% ee.