双官能团醇类化合物催化胺化反应的研究进展

本文综述了由双官能团醇类化合物催化胺化合成二元胺或环胺的研究进展,分别讨论了金属催化剂和固体酸催化剂对双官能团醇类化合物的不同作用机制,考察了反应物结构对 反应活性和选择性的影响,重点介绍了超临界氨流体在二元醇催化胺化反应中的应用,并指出了今后研究的方向.     

An Improved Ruthenium Catalyst for the Environmentally Benign Amination of Primary and Secondary Alcohols

The N‐alkylation of amines in the presence of different ruthenium catalysts generated in situ was investigated. Among the various catalysts tested, the combination of [Ru₃(CO)₁₂] and N‐phenyl‐2‐(dicyclohexylphosphanyl)pyrrole showed the best performance. By applying this novel catalyst, a variety of functionalized alcohols and amines were converted into the corresponding secondary amines in high yield.     

Iron‐Catalyzed Allylic Amination Directly from Allylic Alcohols

Allylic amination, directly from alcohols, has been demonstrated without any Lewis acid activators using an efficient and regiospecific molecular iron catalyst. Various amines and alcohols were employed and the reaction proceeded through the oxidation/reduction (redox) pathway. A direct one‐step synthesis of common drugs, such as cinnarizine and nafetifine, was exhibited from cinnamyl alcohol that produced water as side product.     

1‐(2′‐Anilinyl)prop‐2‐yn‐1‐ol Rearrangement for Oxindole Synthesis

A synthetic method that relies on NIS (N‐iodosuccinimide)‐mediated cycloisomerization reactions of 1‐(2′‐anilinyl)prop‐2‐yn‐1‐ols to gem‐3‐(diiodomethyl)indolin‐2‐ones and 2‐(iodomethylene)indolin‐3‐ones has been developed. The reactions were shown to be chemoselective, with secondary and tertiary alcoholic substrates exclusively giving the 3‐ and 2‐oxindole products, respectively. In the case of the latter, the transformation features an unprecedented double 1,2‐OH and 1,2‐alkyl migration relay. Density functional theory (DFT) calculations based on proposed iodoaminocyclization species provide insight into this unique divergence in product selectivity.     

Catalytic Oxidation of Alcohols and Amines to Value‐Added Chemicals using Water as the Solvent

Designing reactions in aqueous media has been one of the major challenges in modern organic synthesis, especially to avoid the use of large amounts of organic solvents whose disposal is a matter of grave concern from an environmental perspective. The oxidation of alcohols and amines is an essential and important step in the synthesis of many valuable products including polymers and pharmaceuticals. In recent times, there has been a surge in the use of water as a solvent in many organic reactions. This review focuses specifically on the oxidation reactions of alcohols and amines carried out in water media using transition metal catalysts, metal‐free catalysts and photocatalysts.     

硝基芳烃与醇还原胺化:催化剂和催化机制

胺类化合物由于其化学结构和性质上的特点,在合成药物、染料和精细化学品等方面有着重要的应用。胺类化合物的合成方法很多,其中硝基芳烃与醇还原胺化反应由于可以“一锅”法将性质稳定、来源广泛的硝基芳烃、醇转化为各类胺类化合物,且无需提供额外的氢源,从而成为研究的热点。本文即以硝基芳烃与醇还原胺化反应路径为主线,从催化剂及其催化机制两方面对硝基芳烃与醇还原胺化反应的研究进展进行综述,分别对已开发的贵金属催化剂、光催化剂及一些其他类型催化剂作了介绍,重点阐述了催化剂的催化性能、底物适用范围和催化机制。尽管目前各类催化体系都已取得较大的进展,但在一定程度上依然存在着催化剂成本高,底物适应性窄,需要大量使用碱性助剂、溶剂、供氢试剂等问题。基于以上问题,本文指出硝基芳烃与醇还原胺化应重点发展绿色高效、廉价、普适性好、通用性强的催化体系;同时,还要系统地对各种催化剂的催化机制进行深入的研究,为催化体系的开发提供指导。     

Platinum‐Catalyzed Multi‐Step Reaction of Propargyl Alcohols with N‐Heteroaromatics

N‐Methyl indole reacts with but‐2‐yn‐1‐ol in the presence of PtCl₂ in MeOH giving indole derivatives having a substituted 3‐oxobutyl group at the 3‐position in good yield. Under the reaction conditions, various substituted indoles and substituted propargyl alcohols are successfully involved in the reaction giving the corresponding addition products in good to moderate yields. The catalytic reaction can be further extended to N‐phenyl pyrrole. In the present multi‐step reaction, PtCl₂ likely plays dual roles: as the catalyst for the rearrangement of propargyl alcohols to the corresponding alkenyl ketones and as the catalyst for the addition of indoles to the alkenyl ketones. Experimental evidence is provided to support the proposed mechanism.     

Solvent‐Enhanced Diastereo‐ and Regioselectivity in the PdII‐Catalyzed Synthesis of Six‐ and Eight‐Membered Heterocycles via cis‐Aminopalladation

The Pd^II‐catalyzed intramolecular oxidative cyclization of tosyl‐protected cis‐ and trans‐N‐allyl‐2‐aminocyclohexanecarboxamides was examined, and efficient syntheses of cyclohexane‐fused pyrimidin‐4‐ones and 1,5‐diazocin‐6‐ones were developed. In the course of the research, a marked solvent effect was observed on both the regio‐ and diastereoselectivity. Additionally, a novel Pd^II‐mediated domino oxidation, oxidative amination reaction was discovered. Our experimental and theoretical findings suggest that the reactions proceed via a cis‐aminopalladation mechanism.     

Temperature‐Directed Biocatalysis for the Sustainable Production of Aromatic Aldehydes or Alcohols

The biosynthesis of aromatic aldehydes and alcohols from renewable resources is currently receiving considerable attention because of an increase in demand, finite fossil resources, and growing environmental concerns. Here, a temperature‐directed whole‐cell catalyst was developed by using two novel enzymes from a thermophilic actinomycete. Ferulic acid, a model lignin derivative, was efficiently converted into vanillyl alcohol at a reaction temperature at 30 °C. However, when the temperature was increased to 50 °C, ferulic acid was mainly converted into vanillin with a productivity of 1.1 g L^?1 h^?1. This is due to the fact that the redundant endogenous alcohol dehydrogenases (ADHs) are not active at this temperature while the functional enzymes from the thermophilic strain remain active. As the biocatalyst could convert many other renewable cinnamic acid derivatives into their corresponding aromatic aldehydes/alcohols, this novel strategy may be extended to generate a vast array of valuable aldehydes or alcohols.     

Chromium‐Catalyzed Alkylation of Amines by Alcohols

The alkylation of amines by alcohols is a broadly applicable, sustainable, and selective method for the synthesis of alkyl amines, which are important bulk and fine chemicals, pharmaceuticals, and agrochemicals. We show that Cr complexes can catalyze this C?N bond formation reaction. We synthesized and isolated 35 examples of alkylated amines, including 13 previously undisclosed products, and the use of amino alcohols as alkylating agents was demonstrated. The catalyst tolerates numerous functional groups, including hydrogenation‐sensitive examples. Compared to many other alcohol‐based amine alkylation methods, where a stoichiometric amount of base is required, our Cr‐based catalyst system gives yields higher than 90 % for various alkyl amines with a catalytic amount of base. Our study indicates that Cr complexes can catalyze borrowing hydrogen or hydrogen autotransfer reactions and could thus be an alternative to Fe, Co, and Mn, or noble metals in (de)hydrogenation catalysis.