Nitrobenzene and Aniline‐Mediated Direct Olefination of Methyl Substituted N‐Heteroarenes With Benzylic Alcohols

Abstract

Metal‐free, strong‐base‐free, and solvent‐free synthesis of alkenyl heteroarenes through PhNO2/PhNH2 mediated direct olefination of methyl substituted N‐heteroarenes with benzylic alcohols was described. Detailed mechanistic studies indicated that in situ formed imine was the active intermediate for the olefination. PhNO2 protected benzylic alcohols from overoxidation, and PhNH2 not only acted as the coupling partner for the formation of intermediate imine, but also provides an alkaline condition for the generation of enamine salt. Gram scale reaction and the synthesis of three pharmaceutically relevant conjugated olefins were also successful using this methodology.