Iridium-Catalyzed Aerobic α,β-Dehydrogenation of γ,δ-Unsaturated Amides and Acids: Activation of Both α- and β-C–H bonds through an Allyl–Iridium Intermediate
作者:Zhen Wang、Zhiqi He、Linrui Zhang、Yong Huang
DOI:10.1021/jacs.7b11351
日期:2018.1.17
Direct aerobic α,β-dehydrogenation of γ,δ-unsaturated amides and acids using a simple iridium/copper relay catalysis system is described. We developed a new strategy that overcomes the challenging issue associated with the low α-acidity of amides and acids. Instead of α-C-H metalation, this reaction proceeds by β-C-H activation, which results in enhanced α-acidity. Conjugated dienamides and dienoic acids
Redox‐Neutral Nickel(II) Catalysis: Hydroarylation of Unactivated Alkenes with Arylboronic Acids
作者:Dao‐Ming Wang、Wang Feng、Yichen Wu、Tao Liu、Peng Wang
DOI:10.1002/anie.202009195
日期:2020.11.9
additional oxidants and reductants. Mechanistic investigations using kinetic analysis and deuterium‐labelling experiments revealed the protonation to be the rate‐determining step in this redox‐neutral catalysis, and the reversible chain‐walking nature of the newly developed diimine‐Ni catalyst.
此处报道的是氧化还原中性Ni II / Ni II催化循环的发现,该催化循环首次能够将未活化烯烃与芳基硼酸进行线性选择性加氢芳基化。这种新颖的催化循环可通过使用富电子的二亚胺配体实现,具有广泛的底物范围,并且在温和的反应条件下,在没有其他氧化剂和还原剂的情况下具有出色的官能团和杂环相容性。使用动力学分析和氘标记实验的机理研究表明,质子化是该氧化还原中性催化的速率决定步骤,也是新开发的二亚胺-Ni催化剂的可逆链走性质。
Palladium-Catalyzed Ring-Contraction and Ring-Expansion Reactions of Cyclic Allyl Amines
作者:Igor Dubovyk、Dmitry Pichugin、Andrei K. Yudin
DOI:10.1002/anie.201100612
日期:2011.6.20
Ring around the rosy: An amino group can act as the leaving group or the nucleophile in a palladium‐catalyzed allylic amination. As a result, readily accessible cyclic amines can be either ring contracted or ring expanded (see scheme).
[reaction: see text] The readily available N-(O-ethyl thiocarbonylsulfanyl)amides are powerful amidyl radical precursors that undergo 5-exo cyclization to give pyrrolidinone derivatives via a radical-chain reaction initiated by a small amount of lauroyl peroxide.