Vinylogy

The vinylogy principle is a term used in organic chemistry and refers to the phenomenon that two groups of atoms with each other in mesomeric interaction, continue to do so when they are separated by one or more together conjugated C = C double bonds. This is demonstrated in the drawing on the example of a vinylogous carboxylate ion:

The double bond allows the distribution of the negative charges on both oxygen atoms; the anion is similarly stabilized as a carboxylate ion - the underlying γ -keto -enol comes in the acid strength of a carboxylic acid close.

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

The same effect as double bonds also have aromatic rings such as benzene ring. This is known as Phenylogie principle. As an example, the 4- dimethylaminobenzaldehyde led, which can be regarded as " phenyloges dimethylformamide ":