Carbon oxygen bond scission

Carbon-Oxygen Bond Scissions with Boron Trichloride, T. G. Bonner and E. J. Bourne, Methods Carbohydr. Chem., 2, 206-207 (1963). 

Chan, H.W.-S., Prescott, F.A.A., and Swoboda, P.A.T. (1976) Thermal Decomposition of Individual Positional Isomers of Methyl Linoleate Hydroperoxide Evidence of Carbon-Oxygen Bond Scission, J. Am. Oil Chem. Soc. 53, 572-576. 

A rather more complex tertracyclic indole based compound lowers blood pressure by selective blockade of a 1-adrenergic receptors. Reaction of the anion from indole (72-1) with butyrolactone (72-2) leads to the scission of the carbon-oxygen bond in the reagent and the formation of the alkylated product (72-3). The acid is then cyclized onto the adjacent 2 position to give the ketone (72-4) by treatment with a Lewis acid such as polyphosphoric acid. Reaction with bromine then leads to the brominated ketone (72-5). This is subjected to reductive alkylation with ethylene... 

Carbon-oxygen bond cleavage may occur by /1-scission (Fig. 21) but only significantly in cases where relatively stable radicals are the resulting intermediates, such as in the fluorination of f-butylmethyl ether (Fig. 22) [78]. 

We shall see in Chapter 2 that the hybrid radical (A ) formed by reaction (8) and the resulting peroxyl radicals by reaction (9) can assume different stereochemical conformations, which determine the geometric configurations (cis and trans) of the isomeric hydroperoxides from various unsaturated lipids oxidized under different conditions. The oxygen addition reactions (8) and (9) can be reversible for many radicals. The reverse reaction (-9) proceeds by /J-scission or j8-fragmentation of the carbon-oxygen bond (-C-I-00 ) of the peroxyl radicals and may also determine the stereochemical configuration of the isomeric hydroperoxides,... 

On the other hand, in the purely anionic polymerization of five- or higher-membered cyclic esters, the carbonyl carbon of the monomer is attacked with subsequent acyl-oxygen bond scission and reformation of the alkoxide anion. In the coordination polymerization, this is also the carbonyl carbon that is now first coordinated with alkoxide species and then the acyl-oxygen bond is broken with reforming of the covalent alkoxide chain end. In the already formed macromo-lecular chains, the same ester bonds are present as those being the site of the nucleophilic attack in the monomer molecules. These processes are illustrated in Scheme 12, where the active centers are shown as. ..-OMt, for both anionic and covalent centers. 

Photolysis of PVC in the presence of oxygen causes oxidation of the polymer. However, under most (perhaps all) conditions, in both the presence and absence of oxygen, the photodegradation is complicated by scissions of carbon-chlorine bonds. Such scissions may lead to the formation of conjugated polyene sequences via sequential dehydrochlorination (Equation 1). The polyenes... 

Coordination of the ring oxygen atom with a strong electrophile, which withdraws electrons from the oxygen quite effectively and weakens the C—O ring bonds, results either in the scission of one of them or in nucleophilic attack on an adjacent carbon atom. When bond scission occurs, fragmentation or molecular rearrangement may occur. 

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