Umpolung of Indoles: Triflic Acid-Mediated C3-Regioselective Hydroarylation of N-H Indoles

03 March 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


The direct dearomative addition of arenes to the C3-position of unprotected indoles is reported under operationally simple condi-tions, using triflic acid at room temperature. The present regioselective hydroarylation is a straightforward manner to generate an electrophilic indole at the C3-position without the need of a deactivating acetyl group at the indolic nitrogen as in previously reported strategies. This atom economical method delivers biologically relevant 3-arylindolines and 3,3-spiroindolines in high yields and regioselectivities from both intra- and intermolecular processes. DFT computations suggest the stabilization of cationic or dicationic intermediates with H-bonded (TfOH)n clusters.


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