General Types of Organic Reactions

Organic chemical reactions can be organized broadly in two ways—by what kinds of reactions occur and by how those reactions occur. Let s look first at the kinds of reactions that take place. There are four general types of organic reactions additions, eliminations, substitutions, and reammgements. 

A summary of the general types of organic reactions is given in Appendix G. 

In Chapters 10 and 11 we turn our attention to alkenes and alkynes, compounds that contain one and two n bonds, respectively. Because n bonds are easily broken, alkenes and alkynes undergo addition, the third general type of organic reaction. These multiple bonds also make carbon atoms electron rich, so alkenes and alkynes react with a wide variety of electrophilic reagents in addition reactions. 

The photochemical reactions of organic compounds attracted great interest in the 1960s. As a result, many useful and fascinating reactions were uncovered, and photochemistry is now an important synthetic tool in organic chemistry. A firm basis for mechanistic description of many photochemical reactions has been developed. Some of the more general types of photochemical reactions will be discussed in this chapter. In Section 13.2, the relationship of photochemical reactions to the principles of orbital symmetry will be considered. In later sections, characteristic photochemical reactions of alkenes, dienes, carbonyl compounds, and aromatic rings will be introduced. 

There are three general types of metallation reactions (metal-hydrogen exchange) that are commonly used to synthesize organoalkali metal compoimds from organic molecules Direct reaction with an alkali metal, reaction with an alkali metal hydride, or reaction with an organo- or amido-alkali metal. Since these reactions involve acid/base equilibria, they are dependent on both the C-H acidity of the organic molecule and the basicity of the alkali metal source. 

The usefulness of a book of this type depends principally on the compounds selected for inclusion. It is in order then that we describe briefly the basis for selection of the material included. The compounds included satisfy the following criteria (1) the compound either is not available commercially or if available is relatively expensive (2) directions for preparation of the compound had not been included in Organic Syntheses through Volume 28 and (3) the compound is one whose structure is simple and contains reactive functional groups which make it useful as an intermediate, or its preparation involves a generally useful type of organic reaction and the directions may be applied to the preparation of related compounds. 

Green chemistry does not have to be complicated, but it does need to be intentional. Faculty members should look for opportunities to introduce green chemistry concepts and examples into the classroom and the laboratory. A simple example is atom economy, which is a natural fit when discussing the basic types of organic reactions. Addition and rearrangement reactions inherently have a higher atom economy than elimination and substitution reactions. The same concept of atom economy can be introduced into general chemistry in discussions of mass balance. 

This review seeks to establish some general patterns of organic reactions using transition metal complexes and hence to reach some understanding of them. In other words, it discusses how o-bonds are formed from simple molecules and metal complexes, and how they are then transformed into organic compounds, and gives typical examples. There are many types of reactions using transition metal complexes and it is impossible to survey them all, therefore only typical patterns are discussed. The references are by no means exhaus-... 

The term carbonylation was first used by W.Reppe while working with syngas and carbon monoxide chemistry at BASF during the 1930s and 1940s. Carbonylations are catalytic reactions in which carbon monoxide, alone or with other compounds, is incorporated in an organic substrate. There are three general types of carbonylation reactions Reppe reactions, hydroformylations, and Koch carbonylations. 

Nucleophilic substitution reactions, like the examples mentioned at the beginning of this chapter, are among the most fundamental types of organic reactions. In general, we can depict nucleophilic substitution reactions in the following way ... 

This index contains over 25 000 entries to the 6562 text pages of Volumes 1-6. The index covers general types of coordination complex, specific coordination complexes, general and specific organic compounds where their synthesis or use involves coordination complexes, types of reaction (insertion, oxidative addition, etc.), spectroscopic techniques (NMR, IR, etc.), and other topics involving coordination complexes, such as medicinal and industrial applications. 

There are essentially four general types of reaction which organic compounds can undergo ... 

Additional Transformation Reactions. Other reactions that can be catalyzed by mineral surfaces are substitution, elimination, and addition reactions of organic molecules. Substitution and elimination are two general types of reactions that occur at saturated carbon atoms of organic molecules. Both types are initiated by nucleophilic attack however, in elimination reactions it is the basicity of the nucleophile that determine its reactivity rather than its nucleophilicity. Since mineral surfaces are expected to have both nucleophilic and basic properties, these types of reactions should also occur at mineral-water interfaces (see Chapter 22). It remains to be shown whether or not these reactions are catalyzed under environmental conditions. 

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