Gold-Catalyzed Synthesis of Functionalized Pyridines by Using 2H-Azirines as Synthetic Equivalents of Alkenyl Nitrenes


  • We are deeply appreciative of financial support from Ecole Polytechnique to A.P. and G.H. and from ANR to P.F., and we thank Rhodia Chimie Fine (Dr. F. Metz) for a generous gift of HNTf2.


2H-Azirines are easily synthesized from the corresponding ketones and, despite possessing a C[DOUBLE BOND]N bond embedded in a strained three-membered cycle, they are sufficiently stable to be isolated, stored, and manipulated. 2H-Azirines can be regarded as valuable synthetic equivalents of alkenyl nitrenes, however, reactions capitalizing on the cyclic strain of the heterocyclic motif and involving the cleavage of the C[BOND]N single bond remain surprisingly limited. A gold-catalyzed reaction that allows the formation of polysubstituted functionalized pyridines from easily accessible 2-propargyl 2H-azirine derivatives was developed. This transformation, which corresponds to an unprecedented intramolecular transfer of an alkenyl nitrene to an alkyne, proceeds with low catalyst loading, is efficient, and exhibits a high functional-group tolerance and a wide substrate scope.