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Aromatic Aza‐Claisen Rearrangement of Arylpropargylammonium Salts Generated in situ from Arynes and Tertiary Propargylamines
Author(s) -
Han Lu,
Li ShengJun,
Zhang XueTing,
Tian ShiKai
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202004356
Subject(s) - claisen rearrangement , regioselectivity , chemistry , aryne , sigmatropic reaction , carroll rearrangement , triple bond , cope rearrangement , molecule , combinatorial chemistry , organic chemistry , medicinal chemistry , double bond , catalysis
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.