Modular Synthesis of Highly Substituted Pyridines via Enolate 伪-Alkenylation

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• 作者：Leo A. Hardegger ; Jacqueline Habegger ; Timothy J. Donohoe
• 刊名：Organic Letters
• 出版年：2015
• 出版时间：July 2, 2015
• 年：2015
• 卷：17
• 期：13
• 页码：3222-3225
• 全文大小：374K
• ISSN：1523-7052

文摘

A novel methodology for the synthesis of highly substituted pyridines based on the palladium-catalyzed enolate 伪-alkenylation of ketones is presented; the formation of aromatic compounds is a new direction for this catalytic C鈥揅 bond forming reaction. In the key step, a protected 尾-haloalkenylaldehyde participates in 伪-alkenylation with a ketone to afford a 1,5-dicarbonyl surrogate, which then undergoes cyclization/double elimination to the corresponding pyridine product, all in one pot. The 尾-haloalkenylaldehyde starting materials can be obtained from the corresponding methylene ketone via Vilsmeier haloformylation. Using this concise route, a variety of highly substituted pyridines were synthesized in three steps from commercially available compounds.