光氧化还原催化通常依赖于使用单个发色团,而将两种不同的光吸收剂组合在一起的策略很少见。在绿色植物的光系统 I 和 II 中,两个独立的发色团 P 680和 P 700都相互独立地吸收光,然后它们的激发能量在所谓的 Z 方案中组合,以驱动热力学上的整体反应非常严格。在这里,我们采用这个概念在有机基材上进行光氧化还原反应,其中两个红色光子的组合能量输入而不是蓝色或紫外光。具体来说,Cu I双(α-二亚胺)配合物与原位结合在过量的二异丙基乙胺催化下形成 9,10-二氰基蒽自由基阴离子。50 次脱卤和脱甲苯基反应。这种双重光氧化还原方法似乎很有用,因为红光的破坏性较小,并且比蓝光或紫外线辐射具有更大的穿透深度。紫外-可见瞬态吸收光谱表明,溶剂从乙腈到丙酮的细微变化会引起反应机制的转变,包括主要的光诱导电子转移或主要的三重态-三重态能量转移途径。我们的研究说明了在多光子激发条件下运行的系统的机械复杂
features cheap reagent, convenient operations, mild reaction conditions and broad substrate scope. Moreover, this study revealed that the loading of NaH in tosylation reactions of nitrogen-containing compounds with NaH as a base in DMA or DMF should be controlled due to the possibility of adverse detosylation.
was found to act as an efficient oxidant to trigger the [1,2]-arylmigration towards the formation of the desired heterocycles. Depending on the substitution pattern, the results revealed another mechanistic pathway through which benzisoxazoles or 1H-indazoles could be formed. The Beckmann-type rearrangement strategy was applied to the synthesis of benzimidazole-containing biorelevant targets such as
practical intramolecular C–H amidation methodology has been developed using molecular iodine under basic conditions. The required imine substrates were readily obtained by condensation of simple o-phenylenediamine derivatives and aldehydes. The transition-metal-free cyclization reaction described here works well with crude imines and allows for the sequential synthesis of N-protected benzimidazoles
An Unexpected Formation of 2‐Arylbenzimidazoles from α,α‐Diiodo‐α’‐acetoxyketones and
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‐Phenylenediamines
作者:Santu Sadhukhan、Swagata Mondal、Beeraiah Baire
DOI:10.1002/ejoc.202101375
日期:2022.2.11
An unusual, stepwise, two-carbon fragmentation-based mechanistic pathway through domino amidation–aziridination–decarbonylation–I2-mediated aminative cyclization–oxidation has been unravelled for the reaction between α,α-diiodo-α’-acetoxyketones and o-phenylenediamine in the absence of any added reagents such as acids, catalysts or bases as oxidants.