Acylperoxo-Mn

In 1983, Groves and Watanabe succeeded in transforming all conceivable intermediates proposed for P-450 reaction by employing Mn(TMP) [178]. In the work, the use of acylating reagent such as acid halides allowed to be formed a common intermediate in both peroxidase reaction and P-450 reaction, i.e., an acylperoxo-Mn porphyrin complex. The... 

Salcn)IVln "Cl + m-CPBA Catalytic System Characterization of the (Salen)Mn (OOCOAr) Acylperoxo Complex... 

Earlier, Groves and coworkers reported the formation of a manganesc(]II) acylperoxo complex upon interaction of mangancsc(III) porphyrins with pcracids at low temperatures [80,811. Thus, it is natural to suppose that the sharp decrease of the intensity of the EPR signal corresponds to the initial formation of (salcn)Mn (OOCOAr) complex 9. Then, it more slowdy converts into a mononuclear Mn species 10 (Scheme 7). 

The rcaciiviiy of complex 9 towards styrene was estimated indirectly to give a second order rale constant l.l 0.4 M min at -70 °C, the main product of the reaction being styrene oxide [50]. On the contrary, 10 reacted with styrene with noticeable rate only at room temperature to yield mainly bcnzaldehyde along with unidentified chain reaction products [50]. Complex 10 was identified as (salcn)Mn 0 complex [50,82,83]. In Ref. 50 special attention was given to the understanding of donor additives (Jacobsen showed that addition of N-meihylmorpholine-.V-oxidc (NMO) resulted in the higher yields and ees of the epoxides). It was found that NMO dramatically increases the reactivity of the acylperoxo complex 9 towards styrene and the rate of oxidation to 10 (similar to push-effect reported for iron(III) porhyrin acylperoxo complexes [84]). 

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