Preparation of o-Fluorophenols from Nonaromatic Precursors: Mechanistic Considerations for Adaptation to Fluorine-18 Radiolabeling

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• 作者：Norio Yasui ; Christopher G. Mayne ; John A. Katzenellenbogen
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：November 20, 2015
• 年：2015
• 卷：17
• 期：22
• 页码：5540-5543
• 全文大小：301K
• ISSN：1523-7052

文摘

The preparation of fluorine-18 labeled o-fluorophenols at high specific activity is challenging and requires use of [¹⁸F]fluoride ion as the radioisotope source. As a novel, alternative approach, we found that treatment of 伪-diazocyclohexenones with Selectfluor and Et₃N路3HF followed by HF elimination and tautomerization afforded o-fluorophenols regioselectively and rapidly. To adapt this chemistry to ¹⁸F radiolabeling, using bromine electrophiles in place of Selectfluor gave the o-fluorophenol via an 伪-bromo-伪-fluoroketone intermediate in lower but still reasonable yields.