Gatterman-Koch formylation

The Gatterman-Koch formylation is unsuitable for the preparation of aldehydes from phenols and phenolic ethers owing to the formation of complexes with the Lewis acid. 

The Gatterman-Koch synthesis is a variant of the Friedel-Crafts acylation in which carbon monoxide and HC1 generate an intermediate that reacts like formyl chloride. Like Friedel-Crafts reactions, the Gatterman-Koch formylation succeeds only with benzene and activated benzene derivatives. 

Another method, formylation with CO and HCl in the presence of AICI3 and CuCl (the Gatterman-Koch reaction), is limited to benzene and alkylbenzenes. ... 

Arenes can be formylated by generating the active intermediate, CfeC—H, from reagents other than HCOCl. The Gatterman-Koch reaction uses a high-pressure gaseous mixture of CO and HCl. 

The Gatterman aldehyde synthesis employs hydrogen cyanide and unlike the Gatterman-Koch procedure, this method is successful in the case of phenols and phenolic ethers, although only the more reactive hydrocarbons are formylated... 

Another commercial aldehyde synthesis is the catalytic dehydrogenation of primary alcohols at high temperature in the presence of a copper or a copper-chromite catalyst. Although there are several other synthetic processes employed, these tend to be smaller scale reactions. For example, acyl halides can be reduced to the aldehyde (Rosemnund reaction) using a palladium-on-barium sulfate catalyst. Formylation of aryl compounds, similar to hydrofomiylation, using HCN and HQ (Gatterman reaction) or carbon monoxide and HQ (Gatterman-Koch reaction) can be used to produce aromatic aldehydes. 

The formyl cation HCO+ (vco at 2110 cm ) is generated from CO under pressure in the presence of HF/SbFs. Concentrated sulfuric acid or the HCl/CuCl system, activates carbon monoxide toward the electrophilic attack on aromatic hydrocarbons to form aromatic aldehydes (Gatterman-Koch reaction). Branched carboxylic acids are obtained from alkenes and CO in the presence of concentrated sulfuric acid (Koch process) (equation 3). ... 

The electrophilic formylation of arenes with CO in the presence of acids (Gatterman-Koch conditions) is an efficient method for preparing aromatic aldehydes. HF-SbFs-SO2CIF is the most active system for this reaction [82]. It has been demonstrated that even diformylation can be achieved on polymeric aromatics such as biphenyl with the use of fluoroantimonic acid (Eq. 36) [83]. 

In the Gatterman-Koch reaction, a formyl group (-CHO) is introduced directly onin a benzene ring. For example, reaction of toluene with CO and HCI in the presenc of mixed CuCl/AlClg gives p-metbylbenzaldehyde. Propose a mechanism. 

The synthesis of benzaldehyde from benzene poses a problem because formyl chloride, the acyl halide required for the reaction, is unstable and cannot be purchased. Formyl chloride can be prepared, however, by means of the Gatterman-Koch formyla-tion reaction. This reaction uses a high-pressure mixture of carbon monoxide and HCl to generate formyl chloride, along with an aluminum chloride-cuprous chloride catalyst to carry out the acylation reaction. 

Gatterman-Koch reaction A reaction for substituting a formyl (methanoyl) group (HCO-) onto a benzene ring of an aromatic hydrocarbon. It is used in the industrial production of benzaldehyde from benzene ... 

This reaction is related to the Ciamician-Dennstedt Reaction, Duff Reaction, Gatterman Aldehyde Synthesis, and Gattermann-Koch Formylation. 

Whereas electrophilic formylation of aromatics with CO was studied under both the Gatterman-Koch condition and with superacid catalysis in some detail, electrophilic formylation of saturated aliphatics remains virtually unrecognized. 

Aldehydes cannot be synthesized by the Friedel-Crafts reaction using methanoyl chloride (formyl chloride) because it is an unstable compound. However, a gaseous mixture of carbon monoxide and hydrogen chloride reacts like formyl chloride. The formylation of an aromatic compound using this gaseous mixture and aluminum trichloride is called the Gatterman—Koch synthesis. Like the Friedel-Crafts reaction, this method is limited to activated aromatic compounds. 

While not as universal as the Gatterman-Koch reaction, the cation works well for the formylation of activated aromatic com-... 

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