α,α,α',α'-Tetrabromo-o-xylene is an
organobromine compound
Organobromine compounds, also called organobromides, are organic compounds that contain carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons avai ...
with the formula C
6H
4(CHBr
2)
2. Three isomers of α,α,α',α'-Tetrabromoxylene exist, but the ortho derivative is most widely studied. It is an off-white solid. The compound is prepared by the
photochemical reaction Organic photochemistry encompasses organic reactions that are induced by the action of light. The absorption of ultraviolet light by organic molecules often leads to reactions. In the earliest days, sunlight was employed, while in more modern times ...
of
o-xylene with elemental
bromine
Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simila ...
:
:
Reaction of α,α,α',α'-tetrabromo-o-xylene with sodium iodide affords α,α'-dibromo-o-
xylylene
In organic chemistry, a xylylene (sometimes quinone-dimethide) is any of the constitutional isomers having the formula C6H4(CH2)2. These compounds are related to the corresponding quinones and quinone methides by replacement of the oxygen atoms ...
, which can be trapped with
dienophiles to give naphthylene. In the absence of trapping agents, the xylylene relaxes to α,α'-dibromobenzocyclobutane:
:
:
Cycloaddition
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 ...
s of these xylylenes provides a pathway to
acene
In organic chemistry, the acenes or polyacenes are a class of organic compounds and polycyclic aromatic hydrocarbons made up of benzene () rings which have been linearly fused. They follow the general molecular formula .
The larger representa ...
s.
[{{cite journal , doi=10.1055/s-1986-31603, title=An Efficient Synthetic Strategy for Naphthalene Annellation of Norbornenylogous Systems, year=1986, last1=Paddon-Row, first1=Michael N., last2=Patney, first2=Harish K., journal=Synthesis, volume=1986, issue=4, pages=328–330]
References
Organobromides