On the Route to the Photogeneration of Heteroaryl Cations. The Case of Halothiophenes

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• 作者：Carlotta Raviola ; Francesco Chiesa ; Stefano Protti ; Angelo Albini ; Maurizio Fagnoni
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：August 5, 2016
• 年：2016
• 卷：81
• 期：15
• 页码：6336-6342
• 全文大小：454K
• 年卷期：0
• ISSN：1520-6904

文摘

2-Chloro-, 2-bromo-, and 2-iodothiophenes undergo photochemical dehalogenation via the triplet state. In the presence of suitable π-bond nucleophiles, thienylation occurs with modest yield from chloro and bromo derivatives (via photogenerated triplet 2-thienyl cation). Specific trapping by using oxygen along with computational analysis carried out by means of a density functional method support that, in the case of iodo derivatives, homolytic thienyl–I bond fragmentation occurs first and heteroaryl cations are formed by electron transfer within the triplet radical pair, thus opening an indirect access to such cations.