From 1,4-dihalides

Dicarboxylic acids have been prepared from dihalides by this method... 

PARHAM Cyclic ether syruhesis Benzoheterocycle synthesis from dihalides. 

Although the small molecule most commonly split out is water this is not necessarily the case. In the formation of polysulphides from dihalides and sodium polysulphide, sodium chloride is produced. 

Diorganometallic compounds cannot be prepared from dihalides if the halogens are separated by three C-C bonds or less because elimination or other reactions usually predominate. With active metals and 1,1-, 1, 2-, or 1,3-dihalides, the following reactions normally occur ... 

The required hydrogenated heterocycles can easily be prepared from dihalide compounds if the principle of dilution213 is observed (Eq. 3). The... 

Sec. 8.2) from dihalides by base-induced double dehydrohalogenation... 

A suspension of lead oxide in water is used in the preparation of 2,3 butanediol from the corresponding dibromide. Glycols are usually obtained from dihalides through the acetates (method 93). 

Table 5. Dilithiums Prepared from Dihalides with Li Metal ...

The Wittig reaction of phosphorus ylides derived from phosphonium salts with carbonyl compounds to form alkenes is widely used in synthetic chemistry. The alkylation of phosphorus ylides offers a route to a variety of phosphonium salts which can be further manipulated. Bestman and coworkers - have been responsible for a large number of reports based upon this and other aspects of phosphorus chemistry. Their work includes many examples of the intramolecular alkylation of ylides derived from phosphonium salts to form cyclic compounds. The salts can be prepared from dihalides either with triphenylphos-... 

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