Major classes of reactions

At this point, we have seen examples of three major classes of reaction mechanisms ... 

The bis arenes, of which (QH M are the prototypes, and even the M(C6H3F3)2 and M(QF6)2 derivatives,139 are known. However, they are difficult to synthesize and it is the (arene)M(CO)3 compounds, easily obtainable by reactions of arenes with M(CO)6 or M(CO)3(THF)3 that are important. These can undergo three major classes of reactions. 

The nse of polysnlfide complexes in catalysis has been discnssed. Two major classes of reactions are apparent (1) hydrogen activation and (2) electron transfers. For example, [CpMo(S)(SH)]2 catalyzes the conversion of nitrobenzene to aniline at room temperature, while (CpMo(S))2S2CH2 catalyzes a number of reactions snch as the conversion of bromoethylbenzene to ethylbenzene and the rednction of acetyl chloride, as well as the rednction of alkynes to the corresponding cw-alkenes. Electron transfer reactions see Electron Transfer in Coordination Compounds) have been studied because of their relevance to biological processes (in, for example, ferrodoxins), and these cluster compounds are dealt with in Iron-Sulfur Proteins. Other studies include the use of metal polysulfide complexes as catalysts for the photolytic reduction of water by THF and copper compounds for the hydration of acetylene to acetaldehyde. ... 

These divisions may each involve several sorption mechanisms, but if they yield a local reaction that can be accurately described with an appropriate isotherm model, they can be incorporated in equation 2. The behavior and resulting local isotherm forms for three major classes of reactions will be examined here sorption by evolutionally immature soil organic matter sorption by natural mineral phases and sorption by diagenetically altered and evolutionally mature organic matter. 

Three major classes of reaction mechanisms can be identified (1) Radical processes for cobalt and manganese carbonyl complexes that give the expected products with little stereoselectivity [11, 12, 49, 50]. Although some claims have appeared of the intervention of radicals in HDS-related hydrogenation, most of the evidence points to other types of surface mechanisms which can be better related to coordinative mechanisms therefore no further mention will be made of radical reactions in this Chapter. (2) Reactions involving Ziegler-type catalysts (a transition metal complex mixed with an alkyl aluminum co-catalyst) these poorly defined systems have proved to be difficult to study in detail [20, 22-25], and they appear rather unrelated to HDS-active... 

As you study chemistry, you will begin to recognize what types of reactants and conditions lead to certain products. In this section, you will learn to recognize five major classes of reactions, just as an experienced chef can teii a saute from a souffie, you wiii soon be abie to distinguish between combustion and decomposition. 

Over the last decade, a considerable number of reactions has been studied (11,35) (i) olefins oxidation (38,39), hydroboration, and halogenation (40) (ii) amines silylation (41,42), amidation (43), and imine formation (44) (iii) hydroxyl groups reaction with anhydrides (45), isocyanates (46), epichloro-hydrin and chlorosilanes (47) (iv) carboxylic acids formation of acid chlorides (48), mixed anhydrides (49) and activated esters (50) (v) carboxylic esters reduction and hydrolysis (51) (vi) aldehydes imine formation (52) (vii) epoxides reactions with amines (55), glycols (54) and carboxyl-terminated polymers (55). A list of all the major classes of reactions on SAMs plus relevant examples are discussed comprehensively elsewhere (//). The following sections will provide a more detailed look at reactions with some of the common functional SAMs, i.e hydroxyl and carboxyl terminated SAMs. 

Lewis acid mediated intramolecular C-C bond formations represent another major class of reactions adaptable to seven-membered ring synthesis. A superb example of this class is found in the work of Majetich, which features a titanium-induced cyclization reaction employed in the synthesis of several natural products, including bar-batusol (Eq. 4)7 Although technically this closure has a nucleophilic... 

Based on the activation and elementary steps outlined, a variety of catalytic reactions can be better understood and catalytic cycles defined. We consider a few major classes of reactions isomerization, hydrogenation, carbonylation, hydroformylation, oxidation, and metathesis. 

Oxidation, the loss of electrons, and reduction, the gain of electrons, are labels for two major classes of reactions. The reactions described here that are oxidations are alkylation,... 

The versatility of this approach was demonstrated by applying it to seven different substrates (Scheme 3.17). The corresponding chiral products were obtained in very good to excellent conversions (63-99%) and absolute stereoselectivities (>99%), particularly when regiodivergent oxygenations were in principle possible. Thereby, the major classes of reactions in asymmetric synthesis or racemate resolution were investigated (desymmetrization, kinetic resolution, and regiodivergent trans formations). 

Classifying the Countless Despite countless individual reactions, these silver chromate particles form through one of the three major classes of reactions discussed in this chapter. 

In the two preceding sections, we described precipitation reactions (reactions producing a precipitate) and acid-base reactions (reactions involving proton transfer). Here we discuss the third major class of reactions, oxidation-reduction reactions, which are reactions involving a transfer of electrons from one species to another. 

Chemical reactions between biochemical compounds are enhanced by biological catalysts called enzymes, which consist mostly or entirely of globular proteins. In many cases a cofactor is needed to combine with an otherwise inactive protein to produce the catalytically active enzyme complex. The two distinct varieties of cofactors are coenzymes, which are complex organic molecules, and metal ions. Enzymes catalyze six major classes of reactions 1) Oxidoreductases (oxidation-reduction reactions), 2) Transferases (transfer of functional groups), 3) Hydrolases (hydrolysis reactions), 4) Lyases (addition to double bonds, 5) Isomerases (isomerization reactions) and 6) Ligases (formation of bonds with ATP (adenosine triphosphate) cleavage) [1]. 

Enzymes are classified and named according to the nature of the chemical reactions they catalyse. The six major classes of reactions that enzymes catalyse are (with the enzyme... 

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