Carbon-oxygen bonds oxidation additions

Oxidative addition involving carbon-to-oxygen bonds is of relevance to the catalysis with palladium complexes. The most reactive carbon-oxygen bond is that between allylic fragments and carboxylates. The reaction starts with a palladium zero complex and the product is a ir-allylic palladium(II) carboxylate Figure 2.16. 

Poly(phenylene oxide) PPO, or poly(phenylene ether) PPE, is an engineering polymer developed by General Electric. It concerns the oxidative coupling of phenols discovered in 1956 by Allan S. Hay [21], Oxidative coupling leads to the formation of carbon-oxygen bonds between carbon atoms 2,4, and 6 and the phenolic oxygen atom. To avoid coupling with carbon atoms 2 and 6, alkyl substituents at these two positions were introduced. In addition to the polymer a 4,4 dimer is formed, named diphenoquinone (DPQ). The... 

Conjugate addition of methanol to a,/l-unsaturated carbonyl compounds forms a new carbon-oxygen bond to yield valuable ethers (Scheme 26). Kabashima et al. (12) reported the conjugate addition of methanol to 3-buten-2-one on alkaline oxides, hydroxides, and carbonates at a temperature of 273 K. The activities of the catalyst follow the order alkaline earth metal oxides > alkaline earth metal hydroxides > alkaline earth metal carbonates. All alkaline earth metal oxides exhibited high catalytic activities and, as in alcohol condensations and nitroaldol reactions, their catalytic activities were not much affected by exposure to CO2 and air. 

J. Tsuji, Addition Reactions with Formation of Carbon-Oxygen Bonds - The Wacker Oxidation and Related Reactions, in Comprehensive Organic Synthesis (B. M. Trost, I. Fleming, Eds.), Vol. 7, 469, Pergamon Press, Oxford, U. K., 1991. 

Carbon-oxygen bond cleavage also proceeds by oxidative addition sequences. For example, lactones oxidatively add to Ir(I) to give an iridacycloester ... 

Oxidation reactions also include those reactions that involve the formation of new carbon/oxygen bonds. We have already seen an example the addition of hydrogen peroxide to a carbon/carbon double bond to give the 1,2-diol. Such compounds may undergo further oxidation by treatment with periodic acid, HI04, or lead acetate, Pb(OAc)4. These two reagents are complementary, as the... 

On the other hand, ethylene-TPD on p UO3 indicated the desorption of acetaldehyde (490 K). In addition, an unexpected product was also observed. This product was identified as furan (C4H4O, m/e 68, 39) which desorbed at ca. 550 K with a carbon selectivity of ca. 40 %. Furan formation from ethylene on UO3 requiring the formation of one carbon-carbon bond and of one carbon-oxygen bond, is most likely accompanied by oxygen depletion from the UO3 surfaces and subsequent reduction of U cations into lower oxidation states. The observation of furan from ethylene shows that one may obtain oxygenated products with a high carbon number from ethylene (a relatively abundant feed stock) via one single step. 

Ueno S, Mizushima E, Chatani N, Kakiuchi F (2006) Direct observation of the oxidative addition of the aryl carbon-oxygen bond to a ruthenium complex and consideration of the relative reactivity between aryl carbon-oxygen and aryl carbon-hydrogen bonds. J Am Chem Soc 128 16515-16517... 

The present results suggest a ready means for catalytic alcohol formation via carbene-like bihapto formyl and acyl species (e.g., equations (18) and (19)). Precedent exists for the alkoxide formation step of equation (19) (47,48,82,83). Chain growth could occur via the insertion of an unsaturated surface site into a H3C-0M(or R-OM) bond (an oxidative addition) to yield a metal-carbon bond, followed by further carbonylation, as illustrated in equations (20) and (21). There is good precedent for the insertion of metal ions into carbon-oxygen bonds (84,85,86). Hydro-... 

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