Stereospecific Copper(II)-Catalyzed Tandem Ring Opening/Oxidative Alkylation of Donor–Acceptor Cyclopropanes with Hydrazones: Synthesis of Tetrahydropyridazines
Aerobic copper(II)-catalyzed tandem ringopening and oxidative C–H alkylation of donor–acceptorcyclopropanes with bisaryl hydrazones is accomplished to produce tetrahydropyridazines, in which copper(II) plays dual role as a Lewis acid as well as redox catalyst. The reaction is stereospecific, and optically active cyclopropanes can be reacted with high optical purities (89–98% enantiomeric excess)
A DABCO‐catalyzed double cascade cycloaddition reaction of diverse maleimides with bisarylhydrazones has been developed for the synthesis of a variety of synthetically challenging pyrazolo[5,1‐c][1,2,4]triazole derivatives. Dioxygen gas is employed as the sole oxidant in this transformation. It proceeds with high step‐ and atom‐efficiency and shows a broad substrate scope and functional group tolerance
已经开发了DABCO催化的各种马来酰亚胺与双芳基hydr酮的双级联双环加成反应,用于合成多种具有合成挑战性的吡唑并[5,1– c ] [1,2,4]三唑衍生物。在该转化中,将氧气用作唯一的氧化剂。它具有较高的步长和原子效率,并显示出广泛的底物范围和官能团耐受性,使其成为制备完全取代的吡唑并[5,1– c ] [1,2,4]三唑衍生物的实用方法。
Synthesis of Tetrahydropyridazines by a Metal-Carbene-Directed Enantioselective Vinylogous NH Insertion/Lewis Acid-Catalyzed Diastereoselective Mannich Addition
作者:Xinfang Xu、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1002/anie.201203962
日期:2012.9.24
A versatile cascade of reactions, triggered by RhII‐catalyzed diazo decomposition followed by a vinylogous NH insertion/Lewisacidcatalyzed Mannich addition, that produces highly substituted 1,2,3,6‐tetrahydropyridazines in up to 97 % ee with high yield and diastereocontrol has been developed.
An eco-friendly and efficient electrochemical method for the synthesis of 5-amine-1,2,4-triazole derivatives has been developed by employing hydrazones or in situ generation of hydrazones with cyanamide using KI as the catalyst and electrolyte. This strategy could be smoothly conducted with simple reaction conditions at room temperature without the addition of a chemical oxidant in an undivided cell
Electrochemical Synthesis of Pyrazolines and Pyrazoles via [3+2] Dipolar Cycloaddition
作者:Martin Linden、Silja Hofmann、Antonia Herman、Nicole Ehler、Robin M. Bär、Siegfried R. Waldvogel
DOI:10.1002/anie.202214820
日期:2023.2.20
Electrochemically initiated [32] cycloaddition reactions of readily available and less toxic starting materials enable a facile synthesis of pyrazolines and pyrazoles. Application of a biphasic system and sodium iodide in a dual role as mediator and electrolyte allows for selective reactions with outstanding robustness towards scalability.