A quaternary carbon is a

carbon atom Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up ...

bound 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 ...

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 i ...

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 i ...

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 ...

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 al ...

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". ...

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 ...

Volume 2001, Issue 61, Pages 4053–4065 etc. to construct asymmetric quaternary carbon atoms.

References

Chemical nomenclature Organic chemistry