Metalloporphyrin oxygen transfer catalyzed

Oxometalloporphyrins were taken as models of intermediates in the catalytic cycle of cytochrome P-450 and peroxidases. The oxygen transfer from iodosyl aromatics to sulfides with metalloporphyrins Fe(III) or Mn(III) as catalysts is very clean, giving sulfoxides, The first examples of asymmetric oxidation of sulfides to sulfoxides with significant enantioselectivity were published in 1990 by Naruta et al, who used chiral twin coronet iron porphyrin 27 as the catalyst (Figure 6C.2) [79], This C2 symmetric complex efficiently catalyzed the oxidation... 

Recently, Inoue et al. proposed a new strategy for the preparation of asymmetric metalloporphyrin complexes which have no chiral substituents on the porphyrin rings but have diastereotopic porphyrin faces [302-304]. As shown in Fig. 12, dihexyldeuteroporphyrin II is of C2h symmetry and has enantiotopic faces (prochiral) however, the introduction of a strap on one side gives two isomers which are optical antipodes and could be resolved by HPLC [302, 303] These C2-chiral metalloporphyrin complexes are capable of catalyzing asymmetric oxygen transfer reactions. 

Oxidation Catalyzed by Metalloporphyrins. Much attention has been devoted to the metal-catalyzed oxidation of unactivated C—H bonds in the homogeneous phase. The aim of these studies is to elucidate the molecular mechanism of enzyme-catalyzed oxygen atom transfer reactions. Additionally, such studies may eventually allow the development of simple catalytic systems useful in functionalization of organic compounds, especially in the oxidation of hydrocarbons. These methods should display high efficiency and specificity under mild conditions characteristic of enzymatic oxidations. 

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