Vinylogy principle

The vinylogy principle is a term from organic chemistry and describes the phenomenon that two groups of atoms that are in a mesomeric interaction continue to do so even if they are separated from one another by one or more conjugated C = C double bonds. This is demonstrated in the drawing using the example of a vinylogous carboxylate ion:

Mesomeric-stabilized carboxylate anion (top) and vinylogous carboxylate anion (bottom)

The double bond enables the negative charge to be distributed over both oxygen atoms; the anion is just as well stabilized as a carboxylate ion - the underlying γ- keto - enol comes close to a carboxylic acid in acidity.

A well-known example of a vinylogous carboxylic acid is ascorbic acid .

Aromatic rings such as the benzene ring have the same effect as double bonds . This is known as the phenylogy principle. An example is 4- dimethylaminobenzaldehyde , which can be understood as "phenylogous dimethylformamide ":

Mesomeric-stabilized dimethylformamide (above) and 4-dimethylaminobenzaldehyde, a "phenylogous dimethylformamide" (below)

Individual evidence

1. ↑ entry to vinylog. In: Römpp Online . Georg Thieme Verlag, accessed on June 13, 2014.