A quaternary carbon is a
carbon atom
Carbon () is a chemical element with the chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—its atom making four electrons available to form covalent bond, covalent chemical bonds. It belongs to gro ...
bound
Bound or bounds may refer to:
Mathematics
* Bound variable
* Upper and lower bounds, observed limits of mathematical functions
Physics
* Bound state, a particle that has a tendency to remain localized in one or more regions of space
Geography
*B ...
to four other carbon atoms. For this reason, quaternary carbon atoms are found only in
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...
s having at least five carbon atoms. Quaternary carbon atoms can occur in
branched alkane
In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in whi ...
s, but not in linear alkanes.
Synthesis
The formation of
chiral
Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object.
An object or a system is ''chiral'' if it is distinguishable from ...
quaternary
carbon centers has been a synthetic challenge. Chemists have developed asymmetric
Diels–Alder reaction
In organic chemistry, the Diels–Alder reaction is a chemical reaction between a conjugated diene and a substituted alkene, commonly termed the dienophile, to form a substituted cyclohexene derivative. It is the prototypical example of a peric ...
s,
Heck reaction
The Heck reaction (also called the Mizoroki–Heck reaction) is the chemical reaction of an unsaturated halide (or triflate) with an alkene in the presence of a base and a palladium catalyst (or palladium nanomaterial-based catalyst) to form a s ...
,
Enyne cyclization
In organic chemistry, an enyne is an organic compound containing a double bond (alkene) and a triple bond ( alkyne). It is called a conjugated enyne when the double and triple bonds are conjugated.
The term is a contraction of the terms alke ...
,
cycloaddition reaction
In organic chemistry, a cycloaddition is a chemical reaction in which "two or more unsaturated molecules (or parts of the same molecule) combine with the formation of a cyclic adduct in which there is a net reduction of the bond multiplicity". T ...
s,
C–H activation,
Allylic substitution An allylic rearrangement or allylic shift is an organic reaction in which the double bond in an allyl chemical compound shifts to the next carbon atom. It is encountered in nucleophilic substitution.
In reaction conditions that favor a SN1 react ...
,
Pauson–Khand reaction
The Pauson–Khand reaction (or PKR or PK-type reaction) is a chemical reaction described as a 2+2+1.html" ;"title="/nowiki>2+2+1">/nowiki>2+2+1/nowiki> cycloaddition between an alkyne, an alkene and carbon monoxide to form a α,β-cyclopentenone. ...
,
[ Ishizaki, M.; Niimi, Y.; Hoshino, O.; Hara, H.; Takahashi, T. ]Tetrahedron
In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the o ...
Volume 2001, Issue 61, Pages 4053–4065 etc. to construct asymmetric quaternary carbon atoms.
References
Chemical nomenclature
Organic chemistry