Aziridination of Alkenes catalysed by Porphyrinirons: Selection of Catalysts for Optimal Efficiency and Stereospecificity

DOI: 10.1039/P29880001517

Source and publish data:

Journal of the Chemical Society. Perkin transactions II p. 1517 - 1524 (1988)

Update date:2022-08-03

Topics:

Authors:

Mahy, Jean-Pierre

Bedi, Gustave

Battioni, Pierrette

Mansuy, Daniel

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Article abstract of DOI:10.1039/P29880001517

meso-Tetra-arylporphyriniron(III) derivatives catalyse the N-tosylaziridination of aryl-substituted styrenes by tosylimidoiodobenzene, PhINTs, a nitrogen analogue of iodosylbenzene.Three secondary reactions were found to limit the yield of N-tosylaziridination: (i) the formation of toluene-p-sulphonamide, TsNH2, which is presumably derived from hydrolysis of a possible iron-nitrene, Fe=NTs, intermediate, (ii) the conversion of the Fe(TPP)(Cl) (TPP = tetraphenylporphyrin) catalyst into an iron(III) complex where the NTs moiety is inserted into an iron-nitrogen bond of Fe(TPP)(Cl), (iii) an oxidative degradation of the porphyrin catalyst.These secondary reactions were avoided to a great extent by using anhydrous conditions and Fe(TDCPP)(ClO4) (TDCPP = tetrakis-2,6-dichlorophenylporphyrin) as a catalyst instead of Fe(TPP)(Cl) and Fe(TPP)(ClO4).Under these conditions, N-tosylaziridination of styrene, cis- and trans-stilbene, and 1,1-diphenylethylene was performed with yields between 40 and 90percent.Fe(TDCPP)(ClO4) was also found to be the best catalyst for N-tosylaziridination of aliphatic alkenes such as hex-1-ene, cyclo-octene, and cis- and trans-hex-2-enes.Although N-tosylaziridination of the two latter alkenes catalysed by Fe(TPP)(Cl) was not stereospecific, this reaction became stereospecific with Fe(TDCPP)(ClO4) as catalyst.These results show that by a proper choice of the porphyriniron catalyst, relatively good yields of N-tosylaziridination of alkenes by PhINTs 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.