Reducing agents summary

Table 1 gives a broad summary of the reactions of the corrunon classes of reducing agents, In the following sections some typical examples of synthetically useful reductions (in the educt order given on the table) together with some more sophisticated methods of stereoselective hydrogenations will be discussed. 

An incomplete summary of silanes as reducing agents is provided in Table 4. 

In equation 1, the Grignard reagent, C H MgBr, plays a dual role as reducing agent and the source of the arene compound (see Grignard reaction). The Cr(CO)g is recovered from an apparent phenyl chromium intermediate by the addition of water (19,20). Other routes to chromium hexacarbonyl are possible, and an excellent summary of chromium carbonyl and derivatives can be found in reference 2. The only access to the less stable Cr(—II) and Cr(—I) oxidation states is by reduction of Cr(CO)g. 

A useful summary of common oxidising and reducing agents, together with the various transformations which they undergo is given in Table 17A.2. 

In summary, we concluded that the successive reduction method easily provides the bimetallic nanoparticles with the core/shell structure according to versatile design. For example, different reducing agents may be used for the first reduction and the second one, respectively, depending on the property of the metal. In some cases of two kinds of metals with much different redox potentials, however, inverted core/shell nanoparticles are difficult to form even in the successive reduction. The inverted core/shell structure can be realized by an... 

Table 12.38 Summary of advantages and disadvantages of the three most important types of reducing agent for indigo, vat or sulphur dyeing [239]...

In summary, a number of effective chiral reducing agents have been developed based on the modification of LAH. Excellent results have been obtained with aryl alkyl ketones and a,p-acetylenic ketones. However, dialkyl ketones are reduced in much lower enantiomeric excess. This clearly indicates that steric effects alone do not control stereoselectivity in these reductions. Systematic studies have been carried out with the objective of designing improved reagents. A better understanding of the mechanisms and knowledge of the active species is required in order to provide more accurate models of the transition states of the key reduction steps. 

The zinc chlorite obtained was finally converted by sodium hydroxide into sodium chlorite, zine hydroxide being the by-product. After filtration the sodium chlorite solution was concentrated, crystallized, and the crystalline product dried. But the yield was not very satisfactory, as the reduction power of zinc is too high. Regarding this, lead monoxide in an alkaline solution appears to be a more suitable reducing agent. The reaction proceeds according to the summary equation... 

In summary, oxygen reduces significantly the yield of immediate strand breaks following attack of hyaluronic acid by hydroxyl radicals, particularly at pH 7. This effect is mimicked quantitatively by the oxidants tetranitromethane and the copper(II)-aquo complex where the yield of strand breaks was reduced to 0.19 and 0.24 pmol J respectively. It is likely that these interact with some of the hyaluronic-acid free radicals which would otherwise be precursors of strand breakage. Candidates for such reactions may be carbon-centred a-hydroxy radicals which can be expected to be good reducing agents. An example... 

In summary, it appears that, whenever the reaction of hypobromite with the reducing agent occurs rapidly in mildly alkaline solution, a solution of hypochlorite... 

Summary The reactions of undecamethylcyclohexasilylpotassium (1) with various transition metal compounds were examined. Depending on the metal conqiound, 1 can act in four ways (a) as a nucleophile, (b) as a donor ligand, (c) as a strong base, and (d) as a reducing agent. Only (a) and (b) lead to transition metal silyl complexes, while (c) and (d) bring on unwanted side reactions. 

In summary, aryl halides can undergo substitution by addition-elimination, SrnI, or elimination-addition mechanisms under basic conditions. The addition-elimination mechanism is most reasonable when the arene is electron-poor. When the arene is not electron-poor, the SrnI mechanism is most reasonable either when the nucleophile is a heavy atom or is delocalized, when light is required, or when a catalytic amount of a one-electron reducing agent is required. The elimination-addition mechanism is most reasonable when the arene is not electron-poor and when very strong base (pk b > 35) is used. 

Oxophilic organoaluminum compounds are capable of reacting with various aldehydes and ketones as alkylating and reducing agents. A good summary of this area is given by Mole and Jeffery [3]. 

Write the equation for its formation. (3) What was oxidized (4) What was reduced (5) What was the oxidizing agent (6) What was the reducing agent (7) In summary, write three equations, one in which sulphur dioxide is oxidized, one in which it is reduced, and one in which neither action occurs. 

In summary, the ultimate oxygen storage which as discussed above can be related to the reduction behaviour of the Ce02 based systems, is strongly related to the morphology of the CeC>2 particles, the presence of the supported metal and the nature of the reducing agent. 

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