“…2 H -Azirines are widely used for the preparation of various 4–7-membered N-, N,N-, and N,O-heterocycles of varying degrees of unsaturation and different heteroatom arrangements [ 1 , 2 ]. The ability of azirines to open at any of the three bonds of the ring under the action of electrophilic and nucleophilic reagents, as well as transition metal compounds, underlies a powerful strategy for the synthesis of azete [ 3 ], pyrrole [ 4 , 5 , 6 ], oxazole [ 7 , 8 , 9 ], imidazole [ 10 , 11 , 12 ], 1,2,3-triazole [ 13 ], pyridine [ 14 ] derivatives, and other heterocycles, which are hardly accessible with conventional methods. Some of the azirine-ring opening reactions can be applied for the synthesis of ortho -fused, spiro-fused, and bridged heterocycles.…”