Department of Chemistry, Princeton University, Princeton, New Jersey, 08544, USA.
Angew Chem Int Ed Engl. 2016 Aug 16;55(34):9969-73. doi: 10.1002/anie.201604619. Epub 2016 Jul 12.
A new catalytic method is described to access carbocation intermediates via the mesolytic cleavage of alkoxyamine radical cations. In this process, electron transfer between an excited state oxidant and a TEMPO-derived alkoxyamine substrate gives rise to a radical cation with a remarkably weak C-O bond. Spontaneous scission results in the formation of the stable nitroxyl radical TEMPO(.) as well as a reactive carbocation intermediate that can be intercepted by a wide range of nucleophiles. Notably, this process occurs under neutral conditions and at comparatively mild potentials, enabling catalytic cation generation in the presence of both acid sensitive and easily oxidized nucleophilic partners.
描述了一种新的催化方法，通过烷氧基胺自由基阳离子的均裂来获得碳阳离子中间体。在这个过程中，激发态氧化剂和 TEMPO 衍生的烷氧基胺底物之间的电子转移产生了一个具有非常弱的 C-O 键的自由基阳离子。自发的断裂导致稳定的氮氧自由基 TEMPO(.)的形成以及一个反应性的碳阳离子中间体的形成，该中间体可以被广泛的亲核试剂捕获。值得注意的是，这个过程在中性条件下和相对温和的电势下发生，使得在酸敏感和易氧化的亲核试剂存在下，能够进行催化阳离子的生成。
