Initiation in Photoredox C-H Functionalization Reactions. Is Dimsyl Anion a Key Ingredient?
Initiation in Photoredox C-H Functionalization Reactions. Is Dimsyl Anion a Key Ingredient?
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DOI：
10.1021/acs.joc.7b00822
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发表时间：
2017-08-18
影响因子：
3.6
通讯作者：
Rossi, Roberto A.
中科院分区：
文献类型：
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作者：
Buden, Maria E.;Bardagi, Javier I.;Rossi, Roberto A.
以前的研究已经报道了未活化的芳烃与ArX、碱（（KOBU）-Bu-t或（NaOBu）-Bu-t）和有机添加剂在高温下的芳基化。最近，我们表明，该反应在室温下进行，但在没有添加剂的情况下，采用紫外-可见光。然而，机制的细节，可以使用光诱导的碱促进：均裂芳族取代反应（光-BHAS）至今仍然难以捉摸。本文研究了该反应的电子转移步骤（ET）的不同机理路线，以确定从1-卤代金刚烷（起始步骤）形成1-金刚烷基自由基的可能途径。在光化学和光物理实验和计算研究的基础上，我们提出了一个前所未有的引发步骤，该步骤也可应用于DMSO进行的其他ET反应：第一次;据报道，由强碱和形成的二甲氨酰阴离子; DMSO（溶剂）负责诱导烷基卤上光BHAS过程的引发。
Previous studies have reported the arylation of unactivated arenes with ArX, base ((KOBu)-Bu-t or (NaOBu)-Bu-t), and an organic additive at high temperatures. Recently, we showed that this reaction proceeds in the absence of additives at rt but,employs UV-vis However, details of mechanisms that,can use a photoinduced base-promoted: homolytic aromatic substitution reaction (photo-BHAS) have remained elusive until now. This work examines different mechanistic routes of the essential electron-transfer step (ET) of this reaction in order to identify a-possible path for the formation of 1-adamantyl radicals from 1-haloadamantanes (initiation step). On the basis of photochemical and photophysical experiments and computational studies, we propose an unprecedented initiation step that could also be applied to other ET reactions performed DMSO: For, the first time; it is reported that dimsyl anion, formed from a strong base and; DMSO (solvent), is responsible for inducing the initiation by a photo-BHAS process on alkyl halides.