Photochemisch induzierte Reaktionen von 3‐Amino‐2H‐azirinen

Photochemically Induced Reactions of 3‐Amino‐2H‐azirines Irradiation of 3‐(N‐methylanilino)‐2H‐azirines with a mercury low pressure lamp induces the cleavage of the C(2), C(3)‐ring bond thus affording nitrilio‐methanide dipols, substituted by an amino group at C(1). Depending on the substitution pattern at C(3), these intermediates can be trapped by dipolarophiles to yield five‐membered heterocycles with high regioselectivity, or they undergo a 1,4‐H‐shift forming 2‐azabutadiene derivatives. Further, the dipol is protonated at C(1) even by weak CH–acids.