Azomethine ylids from aziridines

Aziridines, azomethine ylids from, cycloadditions, 60, 35 Aziridines, /3-hydroxy-, radical induced cleavage, 58, 41... 

Triazole derivatives also result from the cycloaddition of DEAZD to azomethine ylids derived from electrocyclic ring opening of aziridines.117 121 For example, the tetrahydro-1,2,4-triazole 73 was prepared by thermolysis of the cts-aziridine in the presence of DEAZD in 96% yield (Eq. 8), and... 

The pyrrolo[l,2-c]imidazole (223) was produced by addition of DMAD to an azomethine ylid resulting from photochemical ring opening of a fused aziridine,299 and the adduct 224 resulted from... 

The azomethine ylid 53, generated thermally from the aziridine 52, underwent cycloaddition in near quantitative yield. With DMAD, only one product is possible with EP the sole product was 54, and EPP gave 54 and 55 in 80 20 ratio. This latter result indicates that steric effects are important with the phenylpropiolic ester.52 Nitrones (57) add to benzylideneacenaphthenone (56) forming the spiroisoxazolidines (58), which lose aldehyde fragments on heating or photolysis to give the... 

An interesting spirocyclic thiazolidine ring system has been reported. Starting from the thiazolethione 67 and the aziridine 68, which when heated to 100 °C forms the azomethine ylid 69, undergoes a 1,3-dipolar cycloaddition reaction to afford the cycloadduct 70 as the sole regioisomer <02H393>. 

Irradiation of a benzene solution of the bicyclic compounds 82 at 15°C leads to the formation of a labile intermediate assigned the enediimine structure 83. At 50°C, tliis forms the cw-2,3-dihydropyrazine 84. ° It has been suggested that the ring opening of the diazabicyclohexene ring occurs in a stepwise fashion via an azomethine ylid intermediate such as 85, which would arise from cleavage of the aziridine C—C bond. The major product from the irradiation of the compound 82a in methanol was the imidazoline 86 which is possibly formed by the addition of methanol across the ylid 85 no dihydropyrazine 84 is formed under these conditions. ... 

Sodium hydride I dimethyl sulfoxide Ring closure with sulfonium ylids Aziridine ring from azomethines... 

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