Is the Electrophilicity of the Metal Nitrene the Sole Predictor of Metal-Mediated Nitrene Transfer to Olefins? Secondary Contributing Factors as Revealed by a Library of High-Spin Co(II) Reagents
作者:Anshika Kalra、Vivek Bagchi、Patrina Paraskevopoulou、Purak Das、Lin Ai、Yiannis Sanakis、Grigorios Raptopoulos、Sudip Mohapatra、Amitava Choudhury、Zhicheng Sun、Thomas R. Cundari、Pericles Stavropoulos
DOI:10.1021/acs.organomet.1c00267
日期:2021.6.28
Recent research has highlighted the key role played by the electron affinity of the active metal-nitrene/imido oxidant as the driving force in nitrene additions to olefins to afford valuable aziridines. The present work showcases a library of Co(II) reagents that, unlike the previously examined Mn(II) and Fe(II) analogues, demonstrate reactivity trends in olefin aziridinations that cannot be solely
最近的研究强调了活性金属氮宾/亚氨基氧化剂的电子亲和力所发挥的关键作用,作为氮宾加成到烯烃中以提供有价值的氮丙啶的驱动力。目前的工作展示了一个 Co(II) 试剂库,与之前研究的 Mn(II) 和 Fe(II) 类似物不同,该库展示了烯烃氮丙啶化反应的反应趋势,而这种趋势不能仅用电子亲和力标准来解释。在由各种烷基、芳基和酰基修饰的三苯酰氨基胺支架的帮助下,合成了一系列 Co(II) 催化剂(17 个成员)。单晶 X 射线衍射分析、循环伏安法和 EPR 数据表明,高自旋 Co(II) 位点 ( S = 3/2) 具有最小的 [N 3 N] 配位,氧化还原跨度范围为 1.4 V潜力。令人惊讶的是,Co(II) 介导的苯乙烯氮丙啶化反应表现出的反应模式与假定的金属氮宾的相关亲电性所预期的反应模式不同。尽管金属-氮烯亲电性减弱,但代表性的L 4 Co催化剂(-COCMe 3臂)的运行速度比L 8 Co类似物(-COCF