Azaruthena(II)‐bicyclo[3.2.0]heptadiene: Key Intermediate for Ruthenaelectro(II/III/I)‐catalyzed Alkyne Annulations
作者:Long Yang、Ralf Steinbock、Alexej Scheremetjew、Rositha Kuniyil、Lars H. Finger、Antonis M. Messinis、Lutz Ackermann
DOI:10.1002/anie.202000762
日期:2020.6.26
enabling the preparation of various bridgehead N‐fused [5,6]‐bicyclic heteroarenes through regioselective electrochemical C−H/N−H annulation without chemical metal oxidants. Novel azaruthenabicyclo[3.2.0]heptadienes were fully characterized and identified as key intermediates. Mechanistic studies are suggestive of an oxidatively induced reductive elimination pathway within a ruthenium(II/III) regime
The reaction of N-heteroaromatic compounds, such as 2-aryl-pyrrole, benzimidazole, imidazole, indole, and pyrazole derivatives, with alkynes in the presence of a catalytic amount of a nickel complex results in C–H/N–H oxidative annulation. The reaction shows a high functional group compatibility. While both Ni(0) and Ni(II) complexes show a high catalytic activity, Ni(0) is proposed as a key catalytic
N-杂芳族化合物(例如 2-芳基吡咯、苯并咪唑、咪唑、吲哚和吡唑衍生物)与炔烃在催化量的镍配合物存在下发生反应,导致 C-H/N-H 氧化成环。该反应表现出较高的官能团相容性。虽然Ni(0)和Ni( II )配合物均表现出高催化活性,但Ni(0)被认为是主催化循环中的关键催化物种。在 Ni( II ) 体系的情况下,反应的进行需要催化量的强碱(例如 KOBu t )的存在。与此形成鲜明对比的是,Ni(0) 系统不需要碱。所提出的机制得到了 DFT 研究的支持。
(Benz)Imidazole-Directed Cobalt(III)-Catalyzed C-H Activation of Arenes: A Facile Strategy to Access Polyheteroarenes by Oxidative Annulation
作者:Pratip Kumar Dutta、Subhabrata Sen
DOI:10.1002/ejoc.201801056
日期:2018.11.1
Cobalt catalyzed (benz)imidazole‐directedC–Hactivation of arenes provides access to polyheteroarenes by oxidative annulation.
钴催化(苯并)咪唑导向的芳烃的C–H活化可通过氧化环化获得聚杂芳烃。
Rhodium(III)‐Catalyzed Oxidative Annulation of Amidines with Alkynes
<i>via</i>
Sequential C−H Bond Activation
The first rhodium‐catalyzed oxidative double C−Hactivation/annulation reaction of amidines and alkynes to construct benzimidazoisoquinolines was developed. The operationally simple transformation showed high functional group compatibility and featured the cleavage of the C−H bonds located on a different moiety of the N‐phenylbenzimidamide substrates.
Ruthenium-catalyzed benzimidazoisoquinoline synthesis via oxidative coupling of 2-arylbenzimidazoles with alkynes
作者:Nerella Kavitha、Genji Sukumar、Vemula Praveen Kumar、Prathama S. Mainkar、Srivari Chandrasekhar
DOI:10.1016/j.tetlet.2013.05.106
日期:2013.8
Synthesis of a fused bis-heterocyclic framework, benzimidazoisoquinoline, has been achieved using Ru-catalyzed reaction of alkynes with 2-aryl benzimidazoles in the presence of Cu salts. The method provides an easy access for the generation of a library of benzimidazoisoquinoline derivatives. (C) 2013 Elsevier Ltd. All rights reserved.