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
Graphite-Supported Gold Nanoparticles as Efficient Catalyst for Aerobic Oxidation of Benzylic Amines to Imines and<i>N</i>-Substituted 1,2,3,4-Tetrahydroisoquinolines to Amides: Synthetic Applications and Mechanistic Study
作者:Man-Ho So、Yungen Liu、Chi-Ming Ho、Chi-Ming Che
DOI:10.1002/asia.200900261
日期:2009.10.5
of N‐substituted 1,2,3,4‐tetrahydroisoquinolines in the presence of aqueous NaHCO3 solution gave the corresponding amides in good yields (83–93 %) with high selectivity (up to amide/enamide=93:4) (6 examples). The same protocol can be applied to the synthesis of benzimidazoles from the reaction of o‐phenylenediamines with benzaldehydes under aerobic conditions (8 examples). By simple centrifugation
使用氧气作为末端氧化剂对胺进行选择性氧化是绿色化学中的重要领域。在这项工作中,我们描述了使用石墨负载的金纳米颗粒(AuNPs / C)催化环状和非环状苄胺的好氧氧化为相应的亚胺,具有中等至优异的底物转化率(43-100%)和产品收率(66–99%)(19个例子)。在NaHCO 3水溶液存在下,对N-取代的1,2,3,4-四氢异喹啉进行氧化,得到的酰胺产率高(83-93%),选择性高(酰胺/酰胺= 93:4)( 6个示例)。相同的协议可以从反应被施加到苯并咪唑的合成Ò在好氧条件下将苯二胺与苯甲醛一起使用(8个例子)。通过简单的离心,可以回收AuNPs / C并重复使用十次,以将二苄基胺氧化为N-亚苄基(苯基)甲胺,而不会显着降低催化活性和选择性。可以将协议“ AuNPs / C + O 2 ”调整为克级,通过氧化10 g 1,2,3,4-可以得到8.9 g(84%分离出的产率)3,4-二氢异
Borrowing Hydrogen-Mediated N-Alkylation Reactions by a Well-Defined Homogeneous Nickel Catalyst
作者:Amreen K. Bains、Abhishek Kundu、Sudha Yadav、Debashis Adhikari
DOI:10.1021/acscatal.9b02977
日期:2019.10.4
bench-stable azo-phenolate ligand-coordinated nickel catalyst which can efficiently execute N-alkylation of a variety of anilines by alcohol. We demonstrate that the redox-active azo ligand can store hydrogen generated during alcohol oxidation and redelivers the same to an in-situ-generated imine bond to result in N-alkylation of amines. The reaction has wide scope, and a large array of alcohols can directly
我们在这里报道了一种定义明确且稳定的偶氮酚盐配体配位的镍催化剂,该催化剂可以通过醇有效地进行多种苯胺的N-烷基化。我们证明,氧化还原活性偶氮配体可以存储在醇氧化过程中产生的氢,并将其重新转移到原位产生的亚胺键上,从而导致胺的N-烷基化。该反应的范围很广,并且大量的醇可以直接偶联到各种苯胺上。包括氘标记到基质上的机理研究建立了从醇中借用氢的方法,并指出了存在于配体主链上的氧化还原活性偶氮部分的关键作用。用自由基猝灭剂和更高的k H / k分离捕获形式的酮基中间体醇氧化步骤的D建议将氢原子转移(HAT)完全转移到还原的偶氮主链上,以铺平醇氧化,这与常规的金属-配体双功能机理相反。该实施例清楚地表明,廉价的贱金属催化剂可以在氧化还原活性配体主链的帮助下完成重要的偶联反应。
Ruthenium N‐Heterocyclic Carbene Complexes for Chemoselective Reduction of Imines and Reductive Amination of Aldehydes and Ketones
作者:Lakshay Kathuria、Ashoka G. Samuelson
DOI:10.1002/ejic.202000069
日期:2020.6.30
Chemoselective reduction of imines to secondary amines is catalyzed efficiently by tethered and untethered, half‐sandwich ruthenium N‐heterocyclic carbene (NHC) complexes at room temperature. The untethered Ru‐NHC complexes are more efficient as catalysts for the reduction of aldimines and ketimines than the tethered complexes. Using the best untethered complex as a catalyst, electronic and steric
Verhalten rhodanierter Schiffscher Basen gegenüber Raney-Nickel, Hydrazin und Alkalien. 11. Mitt.: Über organische Rhodanverbindungen
作者:R. Poholoudek-Fabini、D. Fröhling
DOI:10.1002/ardp.19652980705
日期:——
In Gegenwart von Raney‐Nickel als Wasserstoffüberträger findet eine Hydrierung der Azomethinfunktion erst mit sehr großem Überschuß an Metallkatalysator statt, wobei die Rhodangruppe unter Eliminierung des Schwefels quantitativ abgespalten wird. Raney‐Nickel ohne Zufuhr von Wasserstoff führt durch unvollständige Desulfurierung zu Sulfiden. — Mit Hydrazin erfolgt keine Reduktion, sondern Aufspaltung