Category: Free Radical Reactions

If a radical substitution reaction creates a chirality centre in the product, both the R and S enantiomers will be formed. The carbon bearing the unpaired electron is sp2 hybridized, that is, the three groups to which it is bonded lie in a plane. The incoming halogen has equal access to both sides of the plane.…

Free radical intermediates are generally involved in reactions carried out at high temperatures, under the influence of light or in the presence of free radical generators. Even at room temperature, many reactions proceed by a free-radical mechanism, particularly in nonpolar solvents and in the presence of a radical producer. A radical has a choice: it…

Radicals reported in the literature range from extremely unstable, short-lived species to relatively stable that could be isolated as pure substances. Carbon–hydrogen bonds decrease in strength in R–H when R goes from primary to secondary to tertiary. Tertiary alkyl radicals are therefore the most stable; methyl radicals the least stable. C-H bonds next to conjugating…

Radicals generated from another organometallic compound, tetraethyl lead Et4Pb, were the reason for adding this compound to petrol. These radicals react with other radical species, which are involved in the pre-ignition of the petrol vapour in internal combustion engines, and prevent the phenomenon known as ‘knocking’. Nowadays, simple organic compounds such as MeOBut are used instead…

When bonds break and one atom gets both bonding electrons, the process is called heterolysis and the products are ions. When bonds break and the atoms get one bonding electron each, the process is called homolysis and the products are radicals, which may be atoms or molecules, and contain an unpaired electron. Three general methods are used to form free radicals.…

The conclusion that nonplanar radicals can be formed without unusual difficulty is obviously a qualitative statement. We need to apply to radicals and other reactive intermediates the same criteria we use for other structures: that is, to determine their heats of formation and/or strain energies and correlate those parameters with their structures. In principle, the…

There are two possible structures for simple alkyl radicals, planar with the odd electron in a p orbital, or pyramidal with the odd electron in an sp3 orbital. ESR spectra of ·CH3 and other simple alkyl radicals indicate that these radicals have planar structures. There is experimental evidence that alkyl radicals are planar, or pyramidal structures that…

A carbon-centered radical is a structure having an unpaired electron on a carbon atom and a formal charge of zero. Thus, a free radical is an atom or a group of atoms with an unpaired electron. (This definition includes certain stable, inorganic molecules and atoms such as NO, NO2, Na and Cl). O2 is also…