Introduction to Organic Chemical Synthesis

An important concern to chemists is synthesis, the challenge of preparing a particular compound in an economical way and with conhdence that the method chosen will lead to the desired structure. In this section we will introduce the topic of synthesis, emphasizing the need for systematic planning in order to decide what is the best sequence of steps to convert a specihed starting material to a desired product (the target molecule). 

A critical feature of synthetic planning is to reason backward from the target to the starting material. A second is to always use reactions that you know will work. 

Let s begin with a simple example. Suppose you wanted to prepare cyclohexane, given cyclohexanol as the starting material. We haven t encountered any reactions so far that permit us to carry out this conversion in a single step. 

Reasoning backward, however, we know that we can prepare cyclohexane by hydrogenation of cyclohexene. We ll therefore use this reaction as the last step in our proposed synthesis. 

Recognizing that cyclohexene may be prepared by dehydration of cyclohexanol, a practical synthesis of cyclohexane from cyclohexanol becomes apparent. 

---

Introduction to Organic Chemical Synthesis Retrosynthetic Analysis... 

There are three methods for the introduction of fluorine atoms into the solvent molecules, which are common organic chemical synthesis, electrolytic fluorination, and direct fluorination using elemental fluorine (F2 gas), respectively. The direct fluorination is the simplest method to prepare partially fluorinated organic solvents. It makes possible to obtain many interesting fluorinated organic solvents. Among the important solvents for practical lithium batteries, the direct fluorination has already been applied to propylene carbonate (PC) [6] and 1,2-dimethoxyethane (DME) [7] in the late 1960s. 

Acid-base reactions also allow us to examine important ideas about the relationship between the structures of molecules and their reactivity and to see how certain thermodynamic parameters can be used to predict how much of the product will be formed when a reaction reaches equilibrium. Acid-base reactions also provide an illustration of the important role solvents play in chemical reactions. They even give us a brief introduction to organic synthesis. Finally, acid-base chemistry is something that you will find familiar because of your studies in general chemistry. We begin, therefore, with a brief review. 

It is hoped that these volumes will be useful not only to the chemist who wishes to carry out synthesis in the steroid field, but also to the broader group of organic chemists who are interested in carrying out selective and stereo-chemically defined reactions, as well as protective chemistry on extraneous functional groups, during a broad range of synthetic applications. The chapter on the introduction of deuterium and by inference tritium into steroids was included because of the importance of this technique in mechanistic and metabolic studies both in the steroid and nonsteroid field. 

The book presents a review of sixteen important topics in modem homogeneous catalysis. While the focus is on concepts, many key industrial processes and applications that are important in the laboratory synthesis of organic chemicals are used as real world examples. After an introduction to the field, the elementary steps needed for an understanding of the mechanistic aspects of the various catalytic reactions have been described. Chapter 3 gives the basics of kinetics, thus stressing that kinetics, so often neglected, is actually a key part of the foundation of catalysis. 

As with any modern review of the chemical Hterature, the subject discussed in this chapter touches upon topics that are the focus of related books and articles. For example, there is a well recognized tome on the 1,3-dipolar cycloaddition reaction that is an excellent introduction to the many varieties of this transformation [1]. More specific reviews involving the use of rhodium(II) in carbonyl ylide cycloadditions [2] and intramolecular 1,3-dipolar cycloaddition reactions have also appeared [3, 4]. The use of rhodium for the creation and reaction of carbenes as electrophilic species [5, 6], their use in intramolecular carbenoid reactions [7], and the formation of ylides via the reaction with heteroatoms have also been described [8]. Reviews of rhodium(II) ligand-based chemoselectivity [9], rhodium(11)-mediated macrocyclizations [10], and asymmetric rho-dium(II)-carbene transformations [11, 12] detail the multiple aspects of control and applications that make this such a powerful chemical transformation. In addition to these reviews, several books have appeared since around 1998 describing the catalytic reactions of diazo compounds [13], cycloaddition reactions in organic synthesis [14], and synthetic applications of the 1,3-dipolar cycloaddition [15]. 

P Volume 1,1991,283 pp. 109.50/ 69.50 ISBN 1-55938-180-9 CONTENTS Introduction to the Series An Editor s Foreword, Albert Padwa. Preface, Brian Halton. Strain in Organic Chemistry A Perspective, Brian Halton. Gem-Dihalocyclopropanes in Chemical Synthesis, Martin G. Banwell and Monica E. Re-um. 1-Halo- and 1, 2-Dihalocyclopropenes Useful Synthetic Intermediates, Mark S. Baird. Cyciization and Cycloaddition Reactions of Cyclopropenes, Albert Padwa and Glen E. Fryx-ell. New Synthetic Pathways From Cyclobutanones, Edward Lee-Ruff. Cyclic Alkynes, Enynes and Dienynes A Synthetic Challenge, Herbert Meier. Index. 

---