Homologation reaction

A homologation reaction, also known as homologization, is any chemical reaction that converts the reactant into the next member of the homologous series. A Homologous series is a group of compounds that differ by a constant unit, generally a (-CH₂-) group. The reactants undergo a homologation when the number of a repeated structural unit in the molecules is increased. The most common homologation reactions increase the number of methylene (-CH₂-) units in saturated chain within the molecule. For example the reaction of aldehydes or ketones with diazomethane or methoxymethylenetriphenylphosphine to give the next homologue in the series.