Gatterman reaction

Formylation with Zinc Cyanide and HCI The Gatterman Reaction... 

Formylation with Zn(CN)2 and HCI is called the Gatterman reaction It can be applied to alkylbenzenes, phenols and their ethers, and many heterocyclic compounds. However, it cannot be applied to aromatic amines. In the original version of this reaction, the substrate was treated with HCN, HCI, and ZnCl2, but the use of Zn(CN)2 and HCI (HCN and ZnCF are generated in situ) makes the reaction more... 

Treatment of diazonium salts with cuprous chloride or bromide leads to aryl chlorides or bromides, respectively. In either case the reaction is called the Sandmeyer reaction The reaction can also be carried out with copper and HBr or HCl, in which case it is called the Gatterman reaction (not to be confused with 11-16). The Sandmeyer reaction is not useful for the preparation of fluorides or iodides, but for bromides and chlorides it is of wide scope and is probably the best way of introducing bromine or chlorine into an aromatic ring. The yields are usually high. 

Halo derivatives 127 have been obtained in moderate yields from the corresponding amines 126 via the Sandmeyer-Gatterman reaction (Equation 35) <1996CHEC-II(4)307>. 

Alternatively, chlorine or bromine can also be introduced in the benzene ring by treating the diazonlum salt solution with corresponding halogen acid in the presence of copper powder. This Is referred as Gatterman reaction. 

A useful method for the synthesis of 5-chloro-l,2,4-thiadiazoles (206) is the reaction of amidines with trichloromethylsulfenyl chloride (see Equation (30)). 3-Halo derivatives (349) (X = Cl, Br, I) (Equation (57)) have been obtained in moderate yields from the corresponding amines (348) via the Sandmeyer-Gatterman reaction <84CHEC-I(6)463>. 3-Chloro-l,2,4-thiadiazolin-5-ones (350) and (351) can be prepared by reacting chlorocarbonylsulfenyl chloride with carbodiimides or cyanamides respectively (Scheme 79) <84CHEC-I(6)463>. 

Many nitriles have been used. Even aryl nitriles give good yields if they are first treated with HC1 and ZnCl2 and then the substrate added at 0°C.357 In fact, this procedure increases yields with any nitrile. If thiocyanates RSCN are used, thiol esters ArCOSR can be obtained. The Gatterman reaction (1-16) is a special case of the Hoesch synthesis. 

In a variation of the Gatterman reaction an alkyl cyanide RCN is used in place of HCN as a useful way of preparing ketones from reactive aromatic species that do not react well under Friedel-Crafts conditions. The electrophile involved is effectively R—C NH+, although, perhaps, the imino chloride, R(C NH)C1, the analogue of an acyl chloride, RCOCl, is also involved. As in the Gatterman reaction, the imine is an intermediate. 

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. 

Gabriel synthesis, 403 Gatterman reaction, 429 Gatterman-Koch reaction, 307 Gauche conformation, 53, 170, 275 Geometric isomerism, 88 ... 

RSCN are used, thiol esters ArCOSR can be obtained. The Gatterman reaction (11-18) is a special case of the Hoesch synthesis. 

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