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A dienone is a class of
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
s with the general formula , where R is any substituent, but often H. They are formally "derived from 1,4-
diene
In organic chemistry, a diene ( ); also diolefin, ) or alkadiene) is a covalent compound that contains two double bonds, usually among carbon atoms. They thus contain two alk''ene'' units, with the standard prefix ''di'' of systematic nome ...
compounds by conversion of a –CH2– group into –C(=O)– group", resulting in "a
conjugated structure". They are a kind of
enone. The class includes some
heterocyclic compound
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, proper ...
s.
Properties and occurrence
The parent member is divinyl ketone. It is a colorless liquid (
b.p. 38-40 °C) that tends to polymerize upon standing.
Dienones can arise via
tautomerism
In chemistry, tautomers () are structural isomers (constitutional isomers) of chemical compounds that readily interconvert.
The chemical reaction interconverting the two is called tautomerization. This conversion commonly results from the reloca ...
of
resorcinol
Resorcinol (or resorcin) is a phenolic compound. It is an organic compound with the formula C6H4(OH)2. It is one of three isomeric benzenediols, the 1,3-isomer (or ''meta- (chemistry), meta''-isomer). Resorcinol crystallizes from benzene as co ...
s and some
hydroxypyridines.
Being multifunctional, dienones engage in many reactions. They are often good
dienophiles. They function as
ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...
s, forming
metal-alkene complex
In organometallic chemistry, a transition metal alkene complex is a coordination compound containing one or more alkene ligands. The inventory is large.Elschenbroich, C. "Organometallics" (2006) Wiley-VCH: Weinheim. Such compounds are intermediate ...
es such as
tris(dibenzylideneacetone)dipalladium(0)
Tris(dibenzylideneacetone)dipalladium(0) or d2(dba)3
D2, D02, D.II, D II or D-2 may refer to:
Places
* Dublin 2, a Dublin, Ireland postcode
* Mount Dulang-dulang, the second highest mountain of the Philippines
* D2, a line of Moscow Central Diameters
* D2 Place One and Two, at Cheung Yue Street an ...
is an organopalladium compound. The compound is a complex of palladium(0) with dibenzylideneacetone (dba). It is a dark-purple/brown solid, which is modestly soluble in organic solvents. Bec ...
.
Cyclic dienones
Extensive work has been reported on cyclic dienones. The parent of the seven-membered ring series is
tropone
Tropone or 2,4,6-cycloheptatrien-1-one is an organic compound with some importance in organic chemistry as a non-benzenoid aromaticity, aromatic. The compound consists of a ring of seven carbon atoms with three conjugated system, conjugated alkene ...
. It is a not only a dienone but a trieneone.
Cyclohexadienones are a significant class of dienones, the premier members being the ortho- and para-
quinone
The quinones are a class of organic compounds that are formally "derived from aromatic compounds benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with ...
s. Many cyclohexadienones convert to phenols. In the
dienone–phenol rearrangement
The dienone–phenol rearrangement is a Organic reaction, reaction in organic chemistry first reported in 1921 by Karl von Auwers and Karl Ziegler. A common example of dienone–phenol rearrangement is 4,4-disubstituted converting into a stable 3, ...
, they convert to
phenols
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (− O H) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, . Phenolic compounds ar ...
.:
The parent
cyclopentadienone
Cyclopentadienone is an organic compound with molecular formula C5H4O. The parent cyclopentadienone is rarely encountered, because it rapidly dimerizes. Many substituted derivatives are known, notably tetraphenylcyclopentadienone. Such compounds ...
has only a fleeting existence under laboratory conditions, otherwise it dimerizes. The substituted derivative
tetraphenylcyclopentadienone
Tetraphenylcyclopentadienone is an organic compound with the formula . It is classified as a cyclic dienone. It is a dark purple to black crystalline solid that is soluble in organic solvents. It is an easily made building block for many organic a ...
is however robust solid.
See also
*
Dione
*
Penguinone
References
{{Authority control
Enones