Catalytic Asymmetric Synthesis of 3-Hydroxy-3-trifluoromethyl Benzofuranones via Tandem Friedel鈥揅rafts/Lactonization Reaction

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• 作者：Hai Ren ; Pan Wang ; Lijia Wang ; Yong Tang
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：October 2, 2015
• 年：2015
• 卷：17
• 期：19
• 页码：4886-4889
• 全文大小：382K
• ISSN：1523-7052

文摘

A highly enantioselective and regioselective chiral Lewis acid catalyzed tandem Friedel鈥揅rafts/lactonization reaction is reported, providing direct access to plenty of 3-hydroxy-3-trifluoromethyl benzofuran-2-ones in up to 94% yields with up to >99% ee. Mechanistic study reveals that the interactions between the phenolic hydroxyl group and trifluoropyruvate are the most likely contributing factor to the high enantio- and regioselectivity. Optically pure (鈭?-BHFF can be obtained in gram-scale with 0.05 mol % catalyst, demonstrating the potentially utility of this method in medicinal chemistry.