Regioselective Synthesis of 2,3‐Disubstituted Indoles via Interrupted Heyns Rearrangement Involving C−C Bond Cleavage

Abstract

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.