[Co(MeTAA)] Metalloradical Catalytic Route to Ketenes via Carbonylation of Carbene Radicals
作者:Andrei Chirila、Kaj M. Vliet、Nanda D. Paul、Bas Bruin
DOI:10.1002/ejic.201800101
日期:2018.6.7
Activation of these carbene precursors by the metalloradical cobalt(II) catalyst affords CoIII‐carbene radicals, which subsequently react with carbon monoxide to form ketenes. In the presence of a nucleophile (imine, alcohol, or amine) in the reaction medium the ketene is immediately trapped, resulting in the desired products in a one‐pot synthetic protocol. The β‐lactams formed upon reaction with imines
提出了一种针对 β-内酰胺、酰胺和酯的有效合成策略,包括“原位”生成烯酮并随后用亲核试剂捕获。使用廉价且高活性的钴 (II) 四甲基四氮杂 [14] 环烯催化剂 [Co(MeTAA)] 对卡宾自由基中间体进行羰基化,为取代烯酮提供了一种方便的单锅合成方案。N-甲苯磺酰腙用作卡宾前体,从而弥合醛和烯酮之间的差距。通过金属基钴 (II) 催化剂对这些卡宾前体的活化产生 CoIII-卡宾自由基,其随后与一氧化碳反应形成烯酮。在反应介质中存在亲核试剂(亚胺、醇或胺)时,乙烯酮会立即被捕获,从而在单锅合成方案中生成所需的产物。