REACTION OF IRON(III) PORPHYRINS AND IODOSOXYLENE - ACTIVE OXENE COMPLEX OF CYTOCHROME-P-450

Cytochromes P-450 are a unique class of hemoproteins that catalyze the hydroxylation of a wide variety of organic compounds. These enzymes are known to activate molecular oxygen by sequential two-electron reduction followed by 0-0 and C-H bond scission.1,2 It has been proposed that an iron-bound carbene like “oxene” is involved in the oxygen-transfer process.2 This FeO complex, having an overall charge of 3+ and a formal oxidation state of 5+, is formally equivalent to compound I of catalase (CAT) and peroxidase (HRP).1 Indeed cytochromes P-450 can function as a peroxidase and can catalyze organic peroxide supported hydroxylation of various substrates in the absence of NADPH and O2.3,4 Ullrich et al.5 further demonstrated that cytochrome P-450 mediated hydroxylation can occur in the presence of iodosobenzene without the requirement for O2 and NADPH. Presumably transfer of the oxygen atom is achieved via the following processes We here present evidence that regiospecific hydroxylation of C-H bonds by oxygen transfer can occur in iron porphyrin model systems.6. © 1979, American Chemical Society. All rights reserved.