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The Ferrier rearrangement is an 
organic reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, mechanistic organ ...
that involves a nucleophilic substitution
In chemistry, a nucleophilic substitution (SN) is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile) ...
reaction combined with an allylic shift in a glycal
Glycal is a name for cyclic enol ether derivatives of sugars having a double bond between carbon atoms 1 and 2 of the ring. The term "glycal" should not be used for an unsaturated sugar that has a double bond in any position other than between car ...
(a 2,3- unsaturated glycoside
In chemistry, a glycoside is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. ...
). It was discovered by the carbohydrate
A carbohydrate () is a biomolecule composed of carbon (C), hydrogen (H), and oxygen (O) atoms. The typical hydrogen-to-oxygen atomic ratio is 2:1, analogous to that of water, and is represented by the empirical formula (where ''m'' and ''n'' ...
chemist Robert J. Ferrier.
Mechanism
In the first step, a delocalized allyloxocarbenium ion (2) is formed, typically with the aid of aLewis acid
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any ...
like indium(III) chloride or boron trifluoride
Boron trifluoride is the inorganic compound with the formula . This pungent, colourless, and toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds.
Structure and bonding
The g ...
. This ion reacts in situ
is a Latin phrase meaning 'in place' or 'on site', derived from ' ('in') and ' ( ablative of ''situs'', ). The term typically refers to the examination or occurrence of a process within its original context, without relocation. The term is use ...
with an alcohol, yielding a mixture of the α (3) and β (4) anomer
In carbohydrate chemistry, a pair of anomers () is a pair of near-identical stereoisomers or diastereomers that differ at only the anomeric carbon, the carbon atom that bears the aldehyde or ketone functional group in the sugar's open-chain for ...
s of the 2-glycoside, with the double bond shifted to position 3,4.
Examples
Modifications
Forming of C-glycosides
By replacing the alcohol with asilane
Silane (Silicane) is an inorganic compound with chemical formula . It is a colorless, pyrophoric gas with a sharp, repulsive, pungent smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental ...
, C-glycosides can be formed. With triethylsilane (R'=H), the reaction yields a 2,3-unsaturated deoxy sugar.
Nitrogen analogue
An analogous reaction withnitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
as the heteroatom was described in 1984 for the synthesis of the antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...
substance streptazolin.
References
{{reflist, 35em Carbohydrate chemistry Rearrangement reactions Name reactions