Oxygen bonds formed

Amines also react with diacyl peroxides by nucleophilic displacement on the oxygen—oxygen bond forming an ion pair iatermediate (187) ... 

The general trends of this oxidation are consistent with the mechanism depicted in Scheme 6. This involves the complexation of the alkene to the metal followed by its insertion into the palladium-oxygen bond, forming the five-membered pseudocyclic intermediate which decomposes to give the methyl ketone and the palladium- t-butoxy complex. The decomposition of (84a) is similar to that of the rhodium dioxametallacycles previously shown in Scheme 3.42... 

Reductive addition to electron-deficient olefins can be also performed by using nontoxic (diacyloxyiodo)arenes (5, Scheme 3.4) [9]. In this case, the photocleavage of an iodo-oxygen bond forms an alkylcarboxyl radical that in turn decarboxylates to yield the desired alkyl radical. As an example, phenyl vinyl sulfones are easily alkylated (e.g., by the addition of adamantane) in good yields, provided that a good hydrogen donor such as 1,4-cyclohexadiene is present in solution. 

When this happens, a carbon-oxygen bond forms at the same time that the carbon-bromine bond is broken. The net result of this reaction is the substitution of an OH- ion for a Br ion. Because the reaction occurs in a single step, which involves collisions between the two reactants, the rate of this reaction is proportional to the concentration of both reactants. 

A useful assortment of carbon-carbon bond forming reactions such as alkylation of enolates and enamines and carbon-oxygen bond forming reactions such as epoxidation with ylides have been described in this chapter. 

Biermann, U., Fuermeier, S., Metzger, J. O. Some carbon-nitrogen and carbon-oxygen bond forming additions to unsaturated fatty... 

Carbon-Carbon and Carbon-Oxygen Bond-Forming Reactions... 

Cellulose Sulfonates. Cellulose sulfonates are inorganic esters of cellulose and sulfonic acids in which there is a sulfur-oxygen bond formed to link the cellulose and sulfonic acid moieties. Figure 4 depicts the three most common cellulose sulfonates described in the literature, cellulose methanesulfonate (mesylate) (4), cellulose toluenesulfonate (tosylate) (5), and cellulose dansylate (6) (22-25). Cellulose tosylate is the most commonly described cellulose sulfonate in the literature. Cellulose sulfonates are typically prepared in a homogeneous process by dissolving cellulose in a dimethylacetamide/lithium chloride (DMAc/LiCl) mixture and reacting the cellulose with sulfonylchloride in the presence of triethylamine (Fig. 5) (25). Cellulose sulfonates can also be prepared in situ for use as reactive intermediates (26,27). The use of cellulose tosylate as a reactive intermediate is be discussed in more detail later in this report. 

Carbon - Oxygen Bond Forming Reactions at Room Temperature... 

Each reagent adds two oxygen atoms to the same side of the double bond— that is, in a syn fashion—to yield a cyclic intermediate. Hydrolysis of the cyclic intermediate cleaves the metal-oxygen bonds, forming the c -1,2-diol. With OSO4, sodium bisulfite (NaHSOs) is also added in the hydrolysis step. 

SCHEME 1.5 Example of a rhodium-catalyzed carbon-oxygen bond-forming reaction [17]. 

Dotted lines are used to represent bonds that are partially broken or partially formed. The carbon-chlorine bond breaks on one side of the transition state structure while the carbon-oxygen bond forms on the other side. Transition state structures represent species that cannot be isolated because they are too short-lived and present in only infinitesimal concentrations. The structure of the transition state for a reaction is inferred from kinetic data. Transition states are not intermediates. An intermediate is a species with a finite lifetime, and some intermediates can be isolated. An intermediate forms in one reaction, has a discrete structure, and then reacts in a second reaction. 

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