Selective 5-<i>exo-dig</i>Cyclization of<i>in Situ</i>Synthesized<i>N</i>-Boc-2-aminophenyl Ethoxyethynyl Carbenols: Synthesis of Multifunctional Indoles and Their Derivatives
N‐Boc‐ortho‐aminoaryl ketones and ethoxyacetylene through a cascade of reactions in a single operation that included a nucleophile‐triggered 5‐exo‐dig cyclization and an acid‐mediated 1,3‐allyl alcohol isomerization (1,3‐AAI) is described. A variety of aryl, vinyl and alkynyl groups can be introduced at C‐3 of indole‐2‐carboxaldehyde while having a high functional group compatibility. The 3‐alkynyl adducts, which