Diastereoselective Synthesis of C3‐Quaternary Indolenines Using α,β‐Unsaturated N‐Aryl Ketonitrones and Activated Alkynes

New trick for an old dog: C3-Quaternary indolenines were synthesized by combining readily available α,β-unsaturated N-aryl ketonitrones and activated alkynes. This remarkably simple and atom-economical transformation does not require transition-metal catalysis and involves the formation of the heterocycles with concomitant generation of two contiguous quaternary and tertiary chiral centers.