Metal-Free [2+2+2] Cycloaddition of Ynamides and Nitriles: Mild and Regioselective Synthesis of Fully Substituted Pyridines

摘要

Ametal-free trimolecular [2+2+2] cycloaddition of internal ynamides and nitriles for de novo synthesis of fully substituted pyridines is disclosed. With the versatile Bronsted acid catalyst HNTf2, the mild intermolecular cyclotrimerization process proceeds with complementary chemoselectivity and excellent regioselectivity.