Metal‐Free Strategies for Indoles and <i>o</i> ‐Acyl Benzanilides From 2‐Alkynylaniline Derivatives: Experimental and DFT Insights

We describe a metal-free, divergent transformation of acyl-substituted 2-alkynylanilines that yields two distinct products under complementary conditions. Base-mediated intramolecular hydroamination with K₂CO₃ provides 2-substituted indoles, whereas TfOH catalyzes regioselective alkyne hydration to produce o-acyl benzanilides. These protocols operate under mild conditions, allowing product selectivity to be controlled by reaction environment. DFT and TDDFT analyses clarify the key electronic features governing each pathway, explaining the observed chemoselectivity. This study establishes a practical approach for accessing both heterocyclic and carbonyl frameworks from a common precursor.