Tandem Cu-Catalyzed Ketenimines formation and Intramolecular Nucleophile Capture: Synthesis of 1,2-dihydro-2-Iminoquinolines from 1-(o-acetamidophenyl)-Propargyl Alcohols

Abstract

The copper catalyzed ketenimine formation reaction of 1-(o-acetamidophenyl)-propargyl alcohols with various sulfonyl azides is found to undergo a concomitant intramolecular nucleophile attack to generate 1,2-dihydro-2-iminoquinolines after aromatization (via elimination of acetyl and hydroxyl groups) and tautomerization. The reaction produces 4-substituted and 3,4-unsubstituted title compounds in moderate to good yields under mild reaction conditions.