Strategies oxidation-reduction

In the following section, we focus on imaging single-crystal electrode surfaces that are of relevance to electrocatalysis. We will first deal with flat, defect-free terraces as well as with more real surfaces with monoatomic high steps as the most common active sites. We will then explore various strategies for nano structuring surfaces, for example, by repetitive oxidation-reduction cycles (ORCs). 

The efficiency of the [2 + 2]-cycloadditions of 417 was utilized in a strategy for the synthesis of cephalosporin derivatives that carry an acetone or acetic acid ester group in the 3-position (Scheme 6.88) [175]. Liberated in the presence of 2-(trimethylsilyl-oxy)propene, 417 underwent cycloaddition leading to 435, treatment of which with tetrabutylammonium or hydrogen fluoride furnished the A3-cephalosporin 436 admixed with the A2-isomer. This mixture was converted to pure 436 by an oxidation-reduction sequence. In addition to the trimethylsilylenol ether of acetone, the... 

The discussion and classification of reagents is masterful in identifying Ingold s new nomenclature and principles with more widely known oxidation-reduction and acid-base theory. The 1953 lectures at Cornell University, published as Structure and Mechanism in Organic Chemistry, follow this same strategy, showing how old classification schemes overlap with each other and how apparent inconsistencies disappear as old schemes are incorporated into the new one. Nineteenth-century Berzelian electrochemical dualism, revived by Lapworth and Robinson in the cationic/anionic schema, disappears into the electrophilic/nucleophilic language. 

The bromination-oxidation-reduction route has been used in the syntheses of many energetic polynitropolycycloalkanes. Some of these reactions are illustrated in Table 1.6 (see also Chapter 2). A common strategy in these reactions is to use the oxime functionality to incorporate the nitro group, followed by oxidative nitration to gem-dinitro functionality via the Kaplan-Shechter reaction. This has been used in the case of 2,5-dinitronorbornane to synthesize 2,2,5,5-tetranitronorbornane. ... 

In contrast to standard borohydride reductive nanoparticle synthesis, we have developed an alternative strategy to amino acid encapsulated nanoparticles by utilizing a metal nanoparticle (M°-(Ligand))/metal ion (M"+) precursor redox pair with matched oxidation/reduction potentials. Simply, a metal nanoparticle such as Pt°-(Cys) acts as the principal reductant to a complimentary selected metal ion of Au + resulting in a new stabilized metal nanoparticle of Au°-(Cys) and the oxidation product of the original nanoparticle Pt"+. Malow et al. have reported a metathesis/transmetallation type reaction between a platinum colloid and a Au cyanide compound. Similarly, we employed a Pt°-(Cys)/AuCl4 pair and 0.5-2.0 equivalents of Au to Pt -(Cys). XRD analysis of the nanoparticle products revealed differences in crystallinity... 

Complexation/decomplexation of metal ions or of neutral organic molecules, protonation/deprotonation reactions, and oxidation/reduction processes can all be exploited to alter reversibly the stereoelectronic properties of one of the two recognition sites, thus affecting its ability to sustain noncovalent bonds [30-34, 41]. These kinds of switchable [2 catenanes can be prepared following the template-directed synthetic strategy illustrated in Figure 5, wherein one of the two macrocyclic components is preformed and then the other one is clipped around it with the help of noncovalent bonding interactions. 

In combination with the oxidation-reduction protocol, the glycal-based oligosaccharide assembling strategy [89] which has been extensively developed by Danishefsky gives an expedient... 

Furan can give rise to a variety of five membered oxacycles. There are four main strategies oxidation of the furan ring, reduction of the furan ring, addition reactions or cycloaddition followed by cleavage of a carbon-carbon bridge. 

We ll use the Problem-Solving Strategy for Balancing Oxidation-Reduction Reactions by Oxidation States. 

It is well established that microbiota plays a very significant role in the various transformations of arsenic, including mineralization/immobilization, oxidation/ reduction, and methylation/demethylation. Some of these biotransformations lead to less toxic forms of arsenic that can be used in the detoxification of the arsenic-contaminated environments. Biomethylation of arsenic results in formation of mono-, di-, and trimethylarsines which are volatile however, these gaseous arsenic forms are also toxic. In developing a bioremediation strategy to clean the... 

F. X. Tarmer, M. Brurmer, and G. Weisser. A computational investigation of water injection strategies for nitric oxide reduction in large-bore DI diesel engines. SAE Paper 2001-01-1069, 2001. 

The first step was an aldol-Iike reaction of the enolate of 437 with 4-(t-butyldiphenylsilyloxy)butanal where a separable mixture of the two diastereomers 438 and 439 was obtained. Diastereomer 438 could be converted through an oxidation-reduction strategy into the other conformer 439, which was achieved in 74% yield (438 13%). hi order to protect the secondary alcohol group with MOM-chloride, it was necessary to deprotect the primary alcohol group and then reprotect it with pivaloyl chloride, with 440 being obtained. The reaction of MOM-chloride with 439 was rather slow and the desired MOM-ether was only sustained in low yields. After having obtained compound 441, Jones oxidation led to a carboxylic acid, which was directly esterified to 442. Dieckmann cyclization followed by protection with TBSOTf afforded a separable diastereomeric mixture of the tricyclic compound, with 443 as the major product (Scheme 8.11). 

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