Metal-Free Cyclotrimerization for the De Novo Synthesis of Pyridines


  • We thank Prof. Dr. Uwe Rosenthal for his enduring support and his steady interest in our work.


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Two routes, one destination: The metal-free, uncatalyzed [2+2+2] cycloaddition of cyanodiynes can proceed through two different reaction cascades, both yielding pyridines as products (see scheme). The unactivated cyano group can act either as an enophile in Alder–ene or as a dienophile in hetero-Diels–Alder reactions—both of which are rather uncommon for this well-known functional group.