Bormann Niklas, Ward Jas S, Bergmann Ann Kathrin, Wenz Paula, Rissanen Kari, Gong Yiwei, Hatz Wolf-Benedikt, Burbaum Alexander, Mulks Florian F
Institute for Organic Chemistry (iOC), RWTH Aachen University, Landoltweg 1, 52074, Aachen, Germany.
Department of Chemistry, University of Jyvaskyla, P. O. Box. 35, Survontie 9 B, 40014, Jyväskylä, Finland.
Chemistry. 2023 Oct 18;29(58):e202302089. doi: 10.1002/chem.202302089. Epub 2023 Aug 25.
Strong Lewis acids are essential tools for manifold chemical procedures, but their scalable deployment is limited by their costs and safety concerns. We report a scalable, convenient, and inexpensive synthesis of stable diiminium-based reagents with a Lewis acidic carbon centre. Coordination with pyridine donors stabilises these centres; the 2,2'-bipyridine adduct shows a chelation effect at carbon. Due to high fluoride, hydride, and oxide affinities, the diiminium pyridine adducts are promising soft and hard Lewis acids. They effectively produce acylpyridinium salts from carboxylates that can acylate amines to give amides and imides even from electronically intractable coupling partners.
强路易斯酸是多种化学过程的重要工具，但其可扩展应用受到成本和安全问题的限制。我们报道了一种可扩展、便捷且廉价的合成方法，用于制备具有路易斯酸性碳中心的稳定二亚胺基试剂。与吡啶供体配位可稳定这些中心；2,2'-联吡啶加合物在碳上表现出螯合效应。由于对氟化物、氢化物和氧化物具有高亲和力，二亚胺基吡啶加合物有望成为软硬兼具的路易斯酸。它们能有效地从羧酸盐生成酰基吡啶盐，这些酰基吡啶盐甚至可以使电子上难以处理的偶联伙伴的胺发生酰化反应，生成酰胺和酰亚胺。
