Gattermann-Koch

Gattermann-Koch reaction Formylation of an aromatic hydrocarbon to yield the corresponding aldehyde by treatment with CO, HCl and AICI3 at atmospheric pressure CuCl is also required. The reaction resembles a Friedel-Crafts acylation since methanoyl chloride, HCOCl, is probably involved. 

By passing a mixture of carbon monoxide and hydrogen chloride into the aromatic hydrocarbon in the presence of a mixture of cuprous chloride and aluminium chloride which acts as a catalyst (Gattermann - Koch reaction). The mixture of gases probably reacts as the equivalent of the unisolated acid chloride of formic acid (formyl chloride) ... 

The Gattermann-Koch formylatioii was found unsuited to the preparation of aldehydes from phenols and phenol ethers such aldehydes may be obtained by Gatteimann s aldehyde reaction. 

For aromatic hydrocarbons some very efficient formytation and acylation procedures are known (e.g. Friedel-Crafts, Vilsmeier, Gattermann-Koch), They are treated in introductory text books. 

FUELS, SYNTHETIC - LIQUID FUELS] (Vol 12) Gattermann-Koch reaction... 

In the presence of aluminum chloride and a small amount of cuprous haUde, a mixture of hydrogen chloride and carbon monoxide serves as a formyl a ting agent of aromatics (Gattermann-Koch reaction) (107) ... 

The Gattermann-Koch synthesis is suitable for the preparation of simple aromatic aldehydes from ben2ene and its substituted derivatives, as well as from polycychc aromatics. The para isomers are produced preferentially. Aromatics with meta-directing substituents cannot be formylated (108). 

The Gattermann-Koch reaction when appHed to alkenes or alkanes gives ketones or acids but not aldehydes. However, the Vilsmeier aldehyde synthesis can be appHed to aUphatic compounds. For example, 1,2-diaLkoxyethylenes react with /V-methy1foTmani1ide and POCl to give alkoxymalondialdehydes ... 

When aqueous solutions of aromatic and heteroaromatic diazonium salts are treated with cuprous chloride, -bromide, or -cyanide, the corresponding aromatic chlorides, bromides, or cyanides are formed, respectively. In many cases the anions mentioned must be present in excess. This reaction, the Sandmeyer reaction, was discovered by Sandmeyer in 1884. A variant carried out with copper powder and HBr or HC1 was for many years called the Gattermann reaction (Gattermann, 1890). As it is often confused with the Gattermann-Koch reaction (ArH + CO + HC1 ArCHO), and as it is mechanistically not significantly different from Sandmeyer s procedure, the name Gattermann reaction should be avoided. 

Gattermann-Koch reaction 230 Gattermann reaction 230 General acid/base catalysis, see Bronsted catalysis... 

Gabriel synthesis Gattermann aldehyde reaction Gattermann reaction Gattermann-Koch reaction Gomberg-Hey reaction Grignard reaction... 

Formylation may be carried out by use of CO, HC1, and A1C13 (the Gattermann-Koch reaction) it is doubtful whether HCOC1 is... 

While the student is being educated in preparative work it is necessary for him to acquire some knowledge of the incessant progress in the methods of organic chemistry and at the same time to become familiar with the most recent results of research work. For these reasons a series of changes had to be made when this new edition was prepared. In order not to increase the bulk of the book these objects have been attained by sacrificing examples (e.g. lino-lenic acid, crystal violet, Gattermann-Koch aldehyde synthesis) with which, from this point of view, it seemed possible to dispense. 

Gattermann aldehyde synthesis, 9, 2 Gattermann-Koch reaction, 5, 6 Germanes, addition to alkenes and alkynes, 13, 4 Glycals,... 

When rearrangements occur in these systems, the products obtained will often be thermodynamically rather than kinetically determined (62). In some instances—e.g., the Gattermann-Koch reaction—the stability of the complex produced is responsible for the fact that the reaction can be carried out at all (4, 9). 

Adams modification of, 690, 701,702 Gattermann reaction, 593, 606 Gattermann-Koch, reaction 689, 697, 698... 

The only formic acid derivative that allows the direct formylation of aromatics is formyl fluoride1617 since others (halides and the anhydride) that could be used in Friedel-Crafts-type acylations are quite unstable. Other related methods, however, are available to transform aromatic hydrocarbons to the corresponding aldehydes. The most frequently used such formylations are the Gattermann-Koch reaction16 17 and the Gattermann synthesis.10 16 17... 

The Gattermann synthesis is somewhat less selective than the Gattermann-Koch reaction. In the HCN—HC1—A1C13 system, the substrate selectivity is 49.1, with 56.4% of para-isomer formation, whereas the corresponding values for the Zn(CN)2—HC1—A1C13 system in nitromethane solvent are 128 and 63.9%, respectively.90... 

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