The Witkop Cyclization: A Photoinduced C-H Activation of the Indole System
The Witkop Cyclization: A Photoinduced C-H Activation of the Indole System
复制标题
DOI：
10.1002/anie.201307391
复制
发表时间：
2014-01-27
影响因子：
16.6
通讯作者：
Gaich, Tanja
中科院分区：
文献类型：
--
作者：
Gritsch, Philipp J.;Leitner, Christian;Gaich, Tanja
激发态氧化还原过程的研究对有机光化学领域及其在复杂靶分子合成中的应用有着特殊的影响。在这样的光化学过程中，如果选择适当的还原电位和氧化电位，以及电子给体和受体的激发态能，就会发生单电子转移以产生离子自由基中间体。Witkop环化是这种过程的分子内变体，通常以吲哚杂环作为电子供体。该反应的特殊合成价值在于不需要任何吲哚系统的预官能化就能形成C-C键。虽然这种光反应已被应用于天然产物的全合成，但它还没有充分利用。下面详细介绍了Witkop环化的合成方法，旨在促进该反应在复杂分子结构合成中的进一步应用。
Investigations of excited-state redox processes have an exceptional impact on the field of organic photochemistry and its application to the synthesis of complex target molecules. In such a photochemical process a single-electron transfer takes place to produce ion-radical intermediates, if the reduction and oxidation potentials, as well as excited-state energies of electron donors and acceptors are chosen appropriately. The Witkop cyclization constitutes an intramolecular variant of such a process, typically with an indole heterocycle as an electron donor. The specific synthetic value of this reaction lies in a C-C bond formation without requiring any prefunctionalization of the indole system. Although this photoreaction has been applied to the total synthesis of natural products, it has still not been used to its full capacity. The following review details synthetic efforts using the Witkop cyclization, and aims to incite further applications of reaction in the synthesis of complex molecular architectures.