Catalytic oxidations using ruthenium porphyrins - Advances in Catalytic Activation of Dioxygen by Metal Complexes - page 58

Analogous to O-atom transfer from Ru-oxo species, imido transfer can
occur from and species.
Stoichiometric imido transfer from ( 31 ) to alkenes to give
aziridines has been demonstrated when porp = TPP, OEP, TTP, 4-C1-TPP, 4-
MeO-TPP, the reaction being formally analogous to epoxidation using
species; for example, when was used in
in the presence of pyrazole, aziridines are formed in 22 and 10%
yields from cis- and trans- stilbenes, respectively, 75 and 72% yields from
cis- and respectively, and in 67-82% yields for p-
substituted styrenes 207,208 . The Ru is recovered as the
complex Ru(porp)(NHTs)(pz) ( 32 ), the overall stoichiometry being shown in
eq. 43 207,208 . Insertion of the imido group into a C-H bond of alkanes
correspondingly gives the tosylamide; e.g. toluene gives the tosyl derivative
of benzylamine (eq. 44), in 9% yield 208,213,214 , while benzyl alcohol gives
benzaldehyde in 95% yield (eq. 45) 207 . The rate-determining step for the
aziridination of alkenes by was considered to be formation

of a carboradical intermediate (Fig 29, cf. Fig. 8 for epoxide formation);
clean isosbestic points were observed during kinetic studies at 25°C by UV-
vis spectroscopy, the rate-law was simply in each of and