Rates in Biomimetic Epoxidation Reactions

Biomimetic oxidations refer to oxidations carried out by relatively low molecular weight complexes which mimic biological systems in their catalytic efficiency. The subject is covered in recent tomes edited by Meunier [208] and van Eldik and Reedijk [209]. 

Corroles are also tetrapyrrolic macrocycles related to the cobalt-chelating corrin in vitamin B12 and have received considerable interest recently [217]. They are related to porphyrins by ring contraction. Corrolazines are derivative compounds obtained by aza substitution of corroles [218]. Related compounds are phthalocya-nines (tetrabenzotetraazaporphyrin) [219]. Although these are promising systems, so far they seem to have lower activity and selectivity than that of the corresponding porphyrins. 

Fpoxidation by Fe-containing complexes with H2O2 is difficult because H2O2 is readily decomposed by Fe [230-232]. However, there are several examples of workable nonheme systems from the groups of Beller [233], Que [234,235], and Jacobsen [236] (Table 1.9). 

Beller and co workers have reported a complex of FeCl3-6H2O with pyridine- 

6-dicarboxylic acid (H2pydic) (Fig. 1.3a) together with an inorganic base such as 

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