- Copper-Catalyzed (4+1) Cascade Annulation of Terminal Alkynes with 2-(Tosylmethyl)anilines: Synthesis of 2,3-Disubstituted Indoles
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A novel strategy based on Cu-catalyzed (4+1) cascade annulation of terminal alkynes as one-carbon synthons with 2-(tosylmethyl)anilines has been developed for the expeditious synthesis of 2,3-disubstituted indoles, in which in situ generations of aza-o-quinone methides and alkynyl-copper(I) species are involved. This annulation provides an effective method for the assembly of synthetically and structurally interesting 2,3-disubstituted indoles.
- Yan, Xu,Liu, Chun-Fang,An, Xian-Tao,Ge, Xiao-Min,Zhang, Qing,Pang, Lin-Han,Bao, Xu,Fan, Chun-An
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supporting information
p. 8905 - 8909
(2021/11/24)
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- Aromatic Aza-Claisen Rearrangement of Arylpropargylammonium Salts Generated in situ from Arynes and Tertiary Propargylamines
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The charge-accelerated aza-Claisen rearrangement of ammonium salts serves as a key step in the construction of complex nitrogen-containing molecules. However, much less attention has been paid to the aromatic aza-Claisen rearrangement than to the aliphatic one. Herein, we report an unprecedented aromatic aza-Claisen rearrangement of arylpropargylammonium salts, generated in situ from arynes and tertiary propargylamines, delivering structurally diverse 2-propargylanilines in moderate to good yields with high regioselectivity. This rearrangement proceeds in the absence of strong bases or transition metals, is compatible with moisture and air, tolerates a wide variety of functional groups, and is amenable to forming 11- to 13-membered heterocycles with a triple bond. The 2-propargylaniline products were treated with aluminum chloride in ethanol to afford multisubstituted indoles in moderate to excellent yields. Finally, a series of deuterium-labeling experiments was performed to elucidate the reaction mechanism.
- Han, Lu,Li, Sheng-Jun,Zhang, Xue-Ting,Tian, Shi-Kai
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supporting information
p. 3091 - 3097
(2021/01/21)
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