The remarkable reactivity of cytochrome P-450 is believed to derive from an oxoferryl porphyrin cation radical species, so called oxenoid, equivalent to compound I of peroxidase^.^^-^ If 5 is the intermediate responsible for the aromatization in the enzymatic system, the C-2 position of 4 must be more reactive than the (2-19 oxo group. However, oxidation of aldehydes to carboxylic acids by the oxenoid intermediate seems more likely ...
