Synthesis of Substituted Chromenes through the DABCO‐Catalyzed Reaction of But‐3‐yn‐2‐one and Methyl Propiolate with Salicyl N ‐Tosylimines (DABCO=1,4‐diazabicyclo[2.2.2]octane)

The DABCO-catalyzed (DABCO = 1,4-diazabicyclo[2.2.2]octane) reaction of but-3-yn-2-one and methyl propiolate with salicyl N-tosylimines yields highly functionalized chromenes and has been thoroughly investigated; the rational mechanism for the reaction has been demonstrated on the basis of 1H NMR spectroscopic investigation.