PREPARATION OF DIFUNCTIONAL COMPOUNDS

Relationship between Volume 9 and Previous Volumes. Compendium of Organic Synthetic Methods, Voiume 9 presents about 1200 examples of published reactions for the preparation of monofunctional compounds, updating the 10650 in Volumes 1-8. Volume 9 contains about 800 examples of reactions which prepare of difunctional compounds with various functional groups. Reviews have long been a feature of this series and Volume 9 adds almost 90 pertinent reviews in the various sections. Volume 9 contains approximately 1000 fewer entries than Volume 8 for an identical three-year period, primarily for difunctional compunds. Interestingly, there are about 500 fewer citations from the most cited journal (Tetrahedron Letters) than in the previous edition. Whether this represents a trend in the literature or an inadvertent selectivity on my part is unknown, but there has been a clear increase in biochemicai and total synthesis papers which may account for this. 

How to Use the Book to Locate Examples of the Preparation of Difunctional Compounds. The difunctional index on p. xi gives the section and page corresponding to each difunctional product. Thus Section 327 (Alcohol, Thiol-Ester) contains examples of the preparation of hydroxyesters Section 323 (Alcohol, Thiol-Alcohol, Thiol) contains examples of the preparation of diols. 

Many literature preparations of difunctional compounds are extensions of the methods applicable to monofunctional compounds. As an example, the reaction RCI — ROH might be used for the preparation of diols from an appropriate dichloro compund. Such methods are difficult to categorize and may be found in either the monofunctional or difunctional sections, depending on the focus of the original paper. 

The method has been of particular value in the preparation of difunctional compounds. For example, the action of elemental halogen on sodium acetylides or alkynylmagnesium halides gives 1-halo-1-alkynes (70-90%). t Also, halo esters, phenols, or acids result when the appropriate aromatic mercurial is treated. Sometimes p-toyl-sulfonyl chloride is substituted for chlorine gas. p-Iododimethylaniline is easily made in 42-54% yield by the reaction of p-dimethylaminophenyl-lithium and iodine. ... 

The method has been extended to the preparation of difunctional compounds. Dihalides Including the mixed variety are formed in 90 to 98% yields. Primary unsaturated bromides of the type RCH=CHCH,Br have been formed from the corresponding alcohols by the action of phosphorus tribromide and pyridine at a low temperature without any apparent rearrangement. However, the corresponding secondary-carbinol system, RCHOHCH=CH is very susceptible to allylic isomerization. The formation of a, -acetylenic bromides from acetylenic alcohols and phosphorus tribromide is common (40-70%). An acetylenic-allenic isomerization has been observed, viz.,... 

How to Use the Book to Locate Examples of the Preparation of Difunctional Compounds. 

Relationship Between Volume 1 and Volume 2. Compendium of Organic Synthetic Methods, Volume 2, presents more than 1000 examples of published methods for the preparation of monofunctional compounds, updating the 3000 or so in Volume 1. In addition Volume 2 presents a new chapter with about 1000 examples of the preparation of difunctional compounds. Methods for the protection of carboxylic acids, alcohols, phenols, aldehydes, amines, and ketones were included in Volume 1. In Volume 2 protective methods for acetylenes, amides, esters, and olefins are also covered. 

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