When benzylic and allylic alcohols were treated with enolacetate in the presence of a catalytic amount of a rhenium complex, ReBr(CO)5, the carbon-carbon bond formation of the alcohols and enolacetate smoothly proceeded to give the corresponding ketones and aldehyde in moderate to good yields. For the reaction of allylic alcohols, γ,δ-unsaturated carbonylcompounds were obtained in good yields. When
system was mainly suitable for aromatic allylicalcohols, and the yield was excellent as determined via gram-scale synthesis. The main product was double bond near the side of a more electron-rich aryl group when allylicalcohols featuring different substituents at the 1 and 3 positions were used as the substrates. Deuterium-labelled experiments clearly demonstrated that the hydrogen source was the
实现了由布朗斯台德酸催化的高活性烯丙醇的直接无金属脱氧,避免了繁琐的反应步骤并消除了金属污染。通过考察一系列布朗斯台德酸、醇、反应温度等,以10 mol% TsOH·H 2 O为催化剂,2当量时,收率高达94%。以对甲基苯甲醇为还原剂,在 80 °C 反应 2 h。该体系主要适用于芳香族烯丙醇,收率良好克级合成。当使用在 1 位和 3 位具有不同取代基的烯丙醇作为底物时,主要产物是靠近更富电子的芳基一侧的双键。氘标记实验清楚地表明氢源是对甲基苯甲醇的亚甲基,其他对照实验表明存在两种醚中间体。有趣的是,烯丙基苄基醚的原位氢转移是一个关键过程,但动力学同位素效应研究 ( k H / k D= 1.28)表明C-H键断裂不是速率决定步骤。提出了一种可能的机制,涉及碳正离子、醚中间体和氢转移。
10.1016/j.mencom.2024.04.023
作者:Chernenko, Andrey Yu.、Shepelenko, Konstantin E.、Minyaev, Mikhail E.、Chernyshev, Victor M.
DOI:10.1016/j.mencom.2024.04.023
日期:——
Bu
<sub>4</sub>
NHSO
<sub>4</sub>
‐Catalyzed Direct
<i>N</i>
‐Allylation of Pyrazole and its Derivatives with Allylic Alcohols in Water: A Metal‐Free, Recyclable and Sustainable System
functional building blocks. Direct N-allylation of pyrazole and its derivatives as an atom economic strategy to provide allylic amines has been achieved only using commercial Bu4NHSO4 as the metal-free catalyst and water as the solvent without any additives. 11–93% isolated yields were obtained for the N-allylation of pyrazole and its derivatives with allylic alcohols. Bu4NHSO4 could be reused for
烯丙胺是有价值的功能性构件。吡唑及其衍生物的直接N-烯丙基化作为提供烯丙胺的原子经济策略已经实现,仅使用商业 Bu 4 NHSO 4作为无金属催化剂和水作为溶剂而没有任何添加剂。吡唑及其衍生物与烯丙醇的N-烯丙基化获得了 11-93% 的分离产率。布4 NHSO 4可通过简单提取重复使用六次,几乎不损失催化活性,也适用于克级规模生产。烯丙醚和吡唑没有发生反应以得到所需产物表明烯丙醚不是该途径中的活性中间体。密度泛函理论 (DFT) 计算表明,底物、溶剂和催化剂之间存在氢键作用,尤其是烯丙醇和 H 2 O之间形成的氢键作用。不同质子溶剂中的对照实验进一步证明了烯丙醇和水的分子间氢键.
FeCl<sub>3</sub>·6H<sub>2</sub>O Catalyzed Disproportionation of Allylic Alcohols and Selective Allylic Reduction of Allylic Alcohols and Their Derivatives with Benzyl Alcohol
been found to be an efficient catalyst for the disproportionation of allylicalcohols, which provides a convenient method for selective transformation of allylicalcohols to alkenes and α,β-unsaturated ketones. Furthermore, this catalytic system is also effective for highly selective allylicreduction of allylicalcohols, allylic ethers, and allylic acetates with benzyl alcohol under neutral and convenient