A dearomatization reaction is an
organic reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, mechanistic organ ...
in which the reactants are
arenes and the products permanently lose their
aromaticity
In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugation alone. The e ...
.
It is of some importance in synthetic organic chemistry for the organic synthesis of new building blocks
and in
total synthesis
Total synthesis, a specialized area within organic chemistry, focuses on constructing complex organic compounds, especially those found in nature, using laboratory methods. It often involves synthesizing natural products from basic, commercially ...
.
Types of carbocyclic arene dearomization include hydrogenative (
Birch reduction
The Birch reduction or Metal-Ammonia reduction is an organic reaction that is used to convert arenes to Cyclohexa-1,4-diene, 1,4-cyclohexadienes. The reaction is named after the Australian chemist Arthur Birch (organic chemist), Arthur Birch and i ...
), alkylative, photochemical, thermal, oxidative, transition metal-assisted and enzymatic.
Photochemical
Examples of photochemical reactions are those between certain arenes and alkenes forming
+2and
+4cycloaddition
In organic chemistry, a cycloaddition is a chemical reaction in which "two or more Unsaturated hydrocarbon, unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of th ...
adducts.
Enzymatic
Examples of enzymes capable of arene dearomatization
are toluene dixoyhydrogenase, naphthalene dixoyhydrogenase and benzoyl CoA reductase.
Transition metal-assisted
A classic example of transition metal-assisted dearomatization is the
Buchner ring expansion
The Buchner ring expansion is a two-step organic Carbon–carbon bond, C-C bond forming reaction used to access 7-membered Cyclic compound, rings. The first step involves formation of a carbene from ethyl diazoacetate, which cyclopropanation, cycl ...
.
Catalytic asymmetric dearomatization reactions (CADA) are used in
enantioselective synthesis
Enantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of Chirality (chemistry), chirality are formed ...
.
References
{{reflist, colwidth=50em , refs=
[Pigge, F. C. (2015) ''Dearomatization Reactions, in Arene Chemistry: Reaction Mechanisms and Methods for Aromatic Compounds'' (ed J. Mortier), John Wiley & Sons, Inc, Hoboken, NJ. {{doi, 10.1002/9781118754887.ch15]
[Roche, S. P. and Porco, J. A. (2011), ''Dearomatization Strategies in the Synthesis of Complex Natural Products.'' Angew. Chem. Int. Ed., 50: 4068–4093. {{doi, 10.1002/anie.201006017]
[''Dearomatizing Benzene Ring Reductases'' Boll M. J Mol Microbiol Biotechnol 2005;10:132–142 {{doi, 10.1159/000091560]
[''Anaerobic degradation of homocyclic aromatic compounds via arylcarboxyl-coenzyme A esters: organisms, strategies and key enzymes''. Boll M, Löffler C, Morris BE, Kung JW. Environ Microbiol. 2014 Mar;16(3):612-27. {{doi, 10.1111/1462-2920.12328]
[Zhuo, C.-X., Zhang, W. and You, S.-L. (2012), ''Catalytic Asymmetric Dearomatization Reactions''. Angew. Chem. Int. Ed., 51: 12662–12686. {{doi, 10.1002/anie.201204822]
Organic reactions