Thermal rearrangement of 2,3-diaryl-1-phthalimidoaziridines

Oxidative aminoaziridination: past, present, and future

“…Some examples of intramolecular processes were already mentioned above, including rearrangement of 2,3-diaryl-1-phthalimidoaziridines into imines (see Schemes 13,14). 40 Similarly, the product of chemo-and stereoselective addition to disubstituted double bond of phellandrene was transformed into bicyclic heterocycle (Scheme 38). 60 In other examples yields of 3-pyrrolines varied over a wide range (28-96%).…”

“…1,3-Dipolar cycloaddition of 1-phthalimidoaziridines to DMADBesides, intermolecular 1,3-dipolar cycloaddition reactions can compete with the intramolecular processes mentioned above, which dominate when dipolarophiles with low activity are used or very unstable azomethine ylides are generated. Therefore attempts to employ 2,3-diaryl-1-phthalimidoazimines in the 1,3-dipolar cycloaddition give imines -products of rearrangement of unstable intermediate ylides 40. Deviations from the above mentioned stereochemical regularities of the thermal 1,3-dipolar cycloaddition of phthalimidoaziridines have so far been observed only in two cases -in reactions between very active dipolarophiles (DMAD, thioketones) and phthalimidoaziridines with three or even four electron-withdrawing substituents, which proceed at 20-40 °C, methylenemalonic acid.…”

Two-Step Construction of Thiophene–Oxazole Dyads with Fluorescent Properties by the Ring Expansion of Aziridines

“…Two aryl groups at the double bond (thienyl and 4-nitrophenyl) provide a facile thermal rearrangement of intermediate aziridine 2h into imine 7 via the 1,2-migration of the PhthN group accompanying the C–C bond cleavage. Rearrangement of 2h to 7 prevailed over the transformation to oxazole 4h and proceeded regioselectively through the migration of the PhthN group to the more electron-deficient carbon atom …”

Mechanical Force for the Transformation of Aziridine into Imine

“…This charge unbalance seems to induce migration of phthalimido group (Figure 4 F). Nonetheless, we believe that further experimental and computational studies are needed to clarify the detailed mechanisms of our migration reactions: particularly, whether ylide is indeed formed in our reaction, and, if yes, whether its structure is identical with the one formed under thermal conditions [18a, 20] …”