Aldehydes Vilsmeier synthesis

Aromatic and heterocycHc compounds are formylated by reaction with dialkyl- or alkylarylformamides in the presence of phosphoms oxychloride or phosgene (Vilsmeier aldehyde synthesis) (125). The Vilsmeier reaction is a Friedel-Crafts type formylation (126), since the intermediate cation formed by the interaction of phosphoms oxychloride with formamide is a typical electrophilic reagent. Ionic addition compounds of formamide with phosgene or phosphoms oxychloride are also known (127). 

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 ... 

Although POCl is the traditional reagent in the Vilsmeier aldehyde synthesis, phosgene may be employed (27—29). 

Vilsmeier aldehyde synthesis a,/ -Ethylenealdehydes by electrophilic substitution... 

Phosphorus oxide chloride Vilsmeier aldehyde synthesis s. 31, 105... 

Although POCI3 is the traditional reagent in the Vilsmeier aldehyde synthesis, phosgene may be employed and its role, as well as that of the intermediates, has been studied extensively (29-31). 

Vilsmeier aldehyde synthesis with and without replacement of methoxyl by chlorine... 

Replacement of methoxy groups by chlorine in Vilsmeier aldehyde synthesis... 

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