Regioselective synthesis of 2,3‐disubstituted indoles via interrupted Heyns rearrangement involving C‐C bond cleavage

A novel metal free, Brønsted acid mediated and operationally simple strategy has been developed for regioselective synthesis of 2,3‐disubstituted indoles from α ‐hydroxyketones and o ‐aminoaryl ketones in excellent yields. The reaction proceeds via interrupted Heyns rearrangement through the generation of aminoenol intermediate followed by intramolecular trapping and aromatization with C−C bond cleavage and release of corresponding ester. The mechanism was further supported by the identification of ester in GCMS and reaction of cyclic α ‐hydroxydimethylketal, which afforded ester tethered indole derivative.