meso -Tetraary I porp hyri n i ron (I 11) derivatives cata lyse t he Ntosylaziridi nation of aryl -su bst ituted styrenes by tosylimidoiodobenzene, PhlNTs, a nitrogen analogue of iodosylbenzene. Three secondary reactions were found to limit the yield of N-tosylaziridination: (i) the formation of toluene-psulphonamide, TsN H2, which is presumably derived from hydrolysis of a possible iron-nitrene, Fe=NTs, intermediate, (ii) the conversion of the Fe(TPP) (CI) (TPP = tetraphenylporphyrin) catalyst into an iron(ii1) complex where the NTs moiety is inserted into an iron-nitrogen bond of Fe(TPP) (CI), (iii) an oxidative degradation of the porphyrin catalyst. These secondary reactions were avoided to a great extent by using anhydrous conditions and Fe(TDCPP)(CIO,) (TDCPP = tetrakis-2,6-dichlorophenylporphyrin) as a catalyst instead of Fe(TPP) (CI) and Fe(TPP) (CIO,). Under these conditions, N-tosylaziridination of styrene, cis-and trans-stilbene, and 1 ,I -diphenylethylene was performed with yields between 40 and 90%. Fe(TDCPP)(CIO,) was also found to be the best catalyst for N-tosylaziridination of aliphatic alkenes such as hex-I -ene, cyclo-octene, and cis-and trans-hex-2-enes. Although N-tosylaziridination of the two latter alkenes catalysed by Fe(TPP) (CI) was not stereospecific, this reaction became stereospecific with Fe(TDCPP) (CIO,) as catalyst. These results show that by a proper choice of the porphyriniron catalyst, relatively good yields of Ntosylaziridination of alkenes by PhlNTs can be obtained. As for 1,2-disubstituted aliphatic alkenes, syn addition of the NTs moiety to the double bond takes place. A possible mechanism is presented.
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