Molecular oxygen, oxidation ring opening

Marusak RA, Mears CF. 1995. Exploration of selected pathways for metabolic oxidative ring opening of benzene based on estimates of molecular energetics In Valentine JS, Foote CS, Greenberg A, Liebman JE, editors. Active Oxygen in Biochemistry. New York Chapman and Hall. p. 336. 

The authors proposed mechanism involves initial attack of an in sitn formed carbene onto the aldehyde to produce tetrahedral intermediate LXXIII (Scheme 47). Proton transfer wonld produce an acyl anion eqnivalent, bnt is inconsistent with product formation. Instead S 2 displacement to produce ring opened intermediate LXXIV is proposed, followed by proton transfer. At this point, molecular oxygen apparently becomes involved to oxidize nncleophilic alkene LXXV. The active catalyst is then regenerated and observed prodnct is formed. 

The cloning of Pseudomonas denitrificans genes involved in vitamin Bi2 biosynthesis opened the way to the elucidation of the aerobic biosynthetic pathway (97). Twenty enzymes were purified and twenty-two cob genes were identified. In the aerobic pathway corrin ring formation is initiated by oxidation with molecular oxygen. 

Two minor products formed during the oxidation of colupolone (193) with molecular oxygen have been shown to have structures (195) and (196). The main product of oxidation is cohulopone (194), and (195) and (196) are considered to be derived from (194) by epoxidation and subsequent opening of the oxiran ring and intramolecular acetalization. ... 

When a Bronsted acid initiator such as sulfuric acid is used, a low molecular weight polyethylene oxide diol is produced. Protonation of the cyclic ether oxygen is followed by ring opening displacement on the monomer. 

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