Copper-Mediated Domino Cyclization/Trifluoromethylation/Deprotection with TMSCF3: Synthesis of 4-(Trifluoromethyl)pyrazoles

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• 作者：Quande Wang ; Lisi He ; Kin Keung Li ; Gavin Chit Tsui
• 刊名：Organic Letters
• 出版年：2017
• 出版时间：February 3, 2017
• 年：2017
• 卷：19
• 期：3
• 页码：658-661
• 全文大小：436K
• ISSN：1523-7052

文摘

A copper-mediated synthesis of 4-(trifluoromethyl)pyrazoles is described. In one step from readily accessible α,β-alkynic tosylhydrazones, a remarkable domino sequence of cyclization, trifluoromethylation, and detosylation takes place to furnish the 4-CF₃ N-H pyrazole cores with good functional group compatibility. The reaction conditions are mild and convenient, at room temperature in air, using the commercially available trifluoromethyltrimethylsilane (TMSCF₃) as the CF₃ source. The method can be applied to the synthesis of a 4-CF₃ analogue of the anti-inflammatory drug celecoxib.