Chemical reaction which converts between members of a homologous series
In organic chemistry, 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 methylene (−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.[1] For example, the reaction of aldehydes or ketones with diazomethane or methoxymethylenetriphenylphosphine to give the next homologue in the series.
Examples of homologation reactions include:
Kiliani-Fischer synthesis, where an aldose molecule is elongated through a three-step process consisting of:
Nucleophillic addition of cyanide to the carbonyl to form a cyanohydrin
Hydrolysis to form a lactone
Reduction to form the homologous aldose
Wittig reaction of an aldehyde with methoxymethylenetriphenylphosphine, which produces a homologous aldehyde.
Arndt–Eistert reaction is a series of chemical reactions designed to convert a carboxylic acid to a higher carboxylic acid homologue (i.e. contains one additional carbon atom)
Kowalski ester homologation, an alternative to the Arndt-Eistert synthesis. Has been used to convert β-amino esters from α-amino esters through an ynolate intermediate.[2]
Seyferth–Gilbert homologation in which an aldehyde is converted to a terminal alkyne and then hydrolyzed back to an aldehyde.
Some reactions increase the chain length by more than one unit. For example, the DeMayo reaction can be considered a two-carbon homologation reaction.
^Encyclopedia of Inorganic Chemistry doi:10.1002/0470862106.id396
^D. Gray, C. Concellon and T. Gallagher (2004). "Kowalski Ester Homologation. Application to the Synthesis of β-Amino Esters". J. Org. Chem.69 (14): 4849–4851. doi:10.1021/jo049562h. PMID 15230615.
and 21 Related for: Homologation reaction information
In organic chemistry, a homologationreaction, also known as homologization, is any chemical reaction that converts the reactant into the next member...
Homologation (Greek homologeo, ὁμολογέω, "to agree") is the granting of approval by an official authority. This may be a court of law, a government department...
the reaction out of the ketene intermediate. A carboxylic acid derivative with an α-methylene group is a retron for an Arndt-Eistert type homologation. An...
indoles. Reactions are also categorized by the change in the carbon framework. Examples are ring expansion and ring contraction, homologationreactions, polymerization...
The Kowalski ester homologation is a chemical reaction for the homologation of esters. This reaction was designed as a safer alternative to the Arndt–Eistert...
N-dimethylformamide, exhibit low solubility in water. Amides undergo many chemical reactions, although they are less reactive than esters. Amides hydrolyse in hot...
was proposed in 1843 by the French chemist Charles Gerhardt. A homologationreaction is a chemical process that converts one member of a homologous series...
nucleophilic behavior, and SO2, electrophilic behavior. Homologationreactions like the Kowalski ester homologation provide simple examples of insertion process...
material as a fraction of its absolute melting point Homologationreaction, a chemical reaction which produces the next logical member of a homologous...
In the Hooker reaction (1936) an alkyl chain in a certain naphthoquinone (phenomenon first observed in the compound lapachol) is reduced by one methylene...
product, allows this sequence to be used as a homologationreaction for primary alcohols. Examples of this reaction include: Generation of α-azidocarboxylic...
Lee, J.-W. CO2‐Enabled Cyanohydrin Synthesis and Facile Iterative HomologationReactions. Chem. – A Eur. J. 2020. doi: 10.1002/chem.202003623. Gaudry, R...
homologization of aldehydes, and ketones to extended aldehydes, a organic reaction first reported in 1958.[1] The reagent is generally prepared and used in...
1988 ISBN 0-534-07968-7 Iterative Stereospecific Reagent-Controlled Homologation of Pinacol Boronates by Enantioenriched -Chloroalkyllithium Reagents...
ISBN 0-582-27843-0. Dondoni, A.; Merino, P. (1995). "Diastereoselective Homologation of D-(R)-Glyceraldehyde Acetonide using 2-(Trimethylsilyl)thiazole"....
basis for Ford's Group B rally car and was designed to comply with FIA homologation regulations, which required 200 parts kits to be produced and at least...
intermediates in the Wittig reaction and related reactions such as the Seyferth–Gilbert homologation and the Horner–Wadsworth–Emmons reaction. Edwin Vedejs's NMR...
and ribonucleotides. The mechanisms involved in these reactions include reductive homologation processes to build larger, more complex molecules from...
Global Information