Cationic 1,2,3-Triazolium Alkynes: Components To Enhance 1,4-Regioselective Azide–Alkyne Cycloaddition Reactions

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• 作者：Zaira Monasterio ; Maialen Sagartzazu-Aizpurua ; José I. Miranda ; Yuri Reyes ; Jesus M. Aizpurua
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：February 19, 2016
• 年：2016
• 卷：18
• 期：4
• 页码：788-791
• 全文大小：357K
• ISSN：1523-7052

文摘

4-Alkynyl-1,2,3-triazolium cations undergo thermal [3 + 2] cycloaddition reactions with azides roughly 50- to 100-fold faster than comparable noncharged alkynes. Further, the reaction is highly 1,4-regioselective (dr up to 99:1) owing to the selective stabilization of 1,4-TS transition states via conjugative π-acceptor assistance of the alkyne triazolium ring. The novel cationic triazolium alkynes also accelerate the CuAAC reaction to provide bis(1,2,3-triazoles) in an “ultrafast” way (<5 min).