[1 + 3] Cycloadditions of isocyanides to azomethine ylides; synthesis and properties of 1-phthalimidoazetidines

Intra- and intermolecular thermal transformations of 2-acyl- and 2-alkoxycarbonyl-N-phthalimidoaziridines

“…The invertomers of aziridine 1e exist in comparable amounts since the effective volumes of the substituents at the carbon atoms of the aziridine ring in this case are similar (both substituents have a carbonyl group next to the three-membered ring). The coupling constants of compounds 1a,d, and 1e (4.4-4.9 Hz for the major invertomer and 4.7-5.8 Hz for the minor invertomer) indicate trans arrangement of the aziridine protons, which is in accord with the well-known steric specificity of oxidative aminoaziridination [3][4][5][6][7][8][9][10]. We should also note that the signals of the phthalimide group carbon atoms in the 13 C NMR spectra of aziridines 1a-f are broadened as a consequence of a second hindered process, which is slow on the NMR time scale, namely, rotation about the tetrasubstituted N-N bond [4,5,10].…”

“…The addition of these species at multiple bonds of dipolarophiles yields various five-membered nitrogen heterocycles [2]. The generation of azomethinylids upon heating derivatives of N-phthalimidoaziridine and subsequent 1,3-dipolar cycloaddition have been demonstrated experimentally [3][4][5]. On the other hand, heating N-phthalimidoaziridines having acyl [6] or alkoxycarbonyl substituents [7] at the carbon atoms of the aziridine ring in the absence of dipolarophiles leads to oxazoles, which may be attributed to a 1,5-electrocyclization of the intermediate acylazomethinylids accompanied by loss of the phthalimide group.…”

Synthesis and photolysis of N-phthalimidoaziridines with electron-withdrawing substituents

“…The reaction mixture was stirred for 1 h further, filtered through a thin layer of silica gel, and the solvent evaporated in vacuum. 1 H NMR spectrum (DMSO-d 6 Reaction with endo-Tricyclo[6.2.1.0 2,7 ]undeca-4,9-diene-3,6-dione (6). 1 Ethyl Ester of (E)-3-Phenyl-1-phthalimidoaziridine-2-carboxylic Acid (2).…”

“…in the presence of 1,3-dipolarophiles give good yields of products, the formation of which is treated as the result of an intra-(oxazolines, oxazoles) and/or intermolecular (pyrrolines, azetidines) conversion of the corresponding N-phthalimidoazomethinylides [4][5][6]. These reactive intermediates enter into various subsequent conversions, though their addition at the multiple bond of 1,3-dipolarophiles has undoubted preparative value as a general method of synthesizing five-membered nitrogen heterocycles of type C [1-3].…”

“…dimethyl fumarate, ethyl cinnamate, N-phenyl-and N-benzylmaleimide, and to the monoadduct of quinone to cyclopentadiene, endo-tricyclo[6.2.1.0 2,7 ]undeca-4,9diene-3,6-dione (6) [8,9]. The subjects of the investigation were the mono-, bi-, and tetracyclic aziridines 1-5.…”