Introduction scope and limits

For the introduction of keto-functions, a number of variants are available which complement or overlap each other as to their scope. Although some methods seem to be less attractive than others, their use in special cases will become clear after comparison of the scope and limitations of the various methods. A few are represented below (for other variants see refs. 88-93). 

Substituent modification is based on substituent reactivity as outlined in the reactivity chapters brief summaries of the scope and limitations of substituent introduction and modification are given for the following important ring systems as they are dealt with ... 

The purpose of this chapter is to provide an introduction to the scope and limitations of radical cyclization reactions. Emphasis will be placed on the reactivity profile of radicals with respect to chemo-, regio-and stereo-selectivity. Because most sequential radical reactions include at least one cyclization, they are also presented in this chapter. The organization of this chapter is similar to the previous chapter on radical additions. However, the basic principles of radical reactions, selectivity requirements, methods to conduct radical reactions (including experimental techniques), and mechanisms are extensively discussed in the previous chapter, and these aspects will be reiterated rather sparingly. A reader who is not familiar with the principles of radical reactions as applied to synthesis should read the addition chapter (Chapter 4.1, this volume) first. 

Thus far we have been using (+)-ethyl lactate as the alcohol in the first step in the synthesis of silyl ketals. As we mentioned in the introduction, in order for our method to be transferred for use with high-value synthetic intermediates in a complex target-oriented synthesis, we must explore the scope and limitation of our method. We began by evaluating the synthesis of silyl ketals by reversing the order of the alcohol addition (Scheme 30). 

In the U.S. in 1957, McCrone presented a review of fusion methods, techniques, equipment, and applications (12). His definition of fusion methods included the methods and procedures useful in research and analysis, which involved heating a compound or mixture of compounds on a microscope slide (12). His text comprises five parts. Chapter I is an introduction discussing the scope and limitations of fusion microscopy, and Chapter II discusses the commercially available equipment at the time. Chapter III details the general techniques for hot stages, cold stages, and hot bars, characterization and identification of organic compounds, purity estimations,... 

All animating reagents dealt with in this chapter are listed here references to their preparation are found in the section on Experimental Conditions. Stereochemistry is discussed in the relevant sections of Scope and Limitations. The term animation refers to the formation of a carbon-nitrogen bond, not just to the introduction of an amine group. For a quantum Monte Carlo study of electrophilic animation reagents see ref. 51. 

The scope of the chapter will include an introduction to the technique of neutron reflectometry, and how it is applied to the study of surfactant adsorption at the planar solid-solution interface, to obtain adsorbed amounts and details of the structure of the adsorbed layer. The advantages and limitations of the technique will be put in the context of other complementary surface techniques. Recent results on the adsorption of a range of anionic, cationic and nonionic surfactants, and surfactant mixtures onto hydrophilic, hydrophobic surfaces, and surfaces with specifically tailored functionality will be described. Where applicable, direct comparison with the results from complementary techniques will be made and discussed. 

---