The Smiles rearrangement is an organic reaction and a rearrangement reaction named after British chemist Samuel Smiles. It is an intramolecular

nucleophilic aromatic substitution A nucleophilic aromatic substitution is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group, such as a halide, on an aromatic ring. Aromatic rings are usually nucleophilic, but some aromatic compou ...

of the type: Smiles rearrangement

where X in the

arene compound Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one or more aromatic rings. The parent member of aromatic compounds is benzene. The word "aromatic" originates from the past groupin ...

can be a

sulfone In organic chemistry, a sulfone is a organosulfur compound containing a sulfonyl () functional group attached to two carbon atoms. The central hexavalent sulfur atom is double-bonded to each of two oxygen atoms and has a single bond to each of ...

, a sulfide, an

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be ...

or any substituent capable of dislodging from the arene carrying a negative charge. The terminal functional group in the chain end Y is able to act as a strong nucleophile for instance an alcohol,

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen Hydrogen is the chemical element wi ...

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

. As in other

s the arene requires activation by an

electron-withdrawing group In chemistry, an electron-withdrawing group (EWG) is a substituent that has some of the following kinetic and thermodynamic implications: *with regards to electron transfer, electron-withdrawing groups enhance the oxidizing power tendency of the ...

preferably in the

aromatic ortho position Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon. ''Ortho'', ''meta'', and ''para'' substitution * I ...

. In one modification called the Truce–Smiles rearrangement the incoming nucleophile is sufficiently strong that the arene does not require this additional activation, for example when the nucleophile is an

organolithium In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom ...

. This reaction is exemplified by the conversion of an

aryl In organic chemistry, an aryl is any functional group or substituent derived from an aromaticity, aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar ...

into a sulfinic acid by action of ''n''-butyllithium: Truce Smiles rearrangement

This particular reaction requires the interaction of the alkyllithium group ortho to the sulfone group akin a

directed ortho metalation Directed ortho metalation (DoM) is an adaptation of electrophilic aromatic substitution in which electrophiles attach themselves exclusively to the ortho- position of a direct metalation group or DMG through the intermediary of an aryllithium com ...

. A conceptually related reaction is the

Chapman rearrangement Carboximidates (or more general imidates) are organic compounds, which can be thought of as esters formed between a carboximidic acid (R-C(=NR')OH) and an alcohol, with the general formula R-C(=NR')OR". They are also known as imino ethers, si ...

. A radical version of Smiles rearrangement is reported by Stephenson in 2015. The

Hayashi rearrangement The Hayashi rearrangement is the chemical reaction of ''ortho''-benzoylbenzoic acids catalysis, catalyzed by sulfuric acid or phosphorus pentoxide. This reaction proceeds through electrophilic acylium ion attack with a Spiro compound, spiro inter ...

can be considered as the cationic counterpart of Smiles rearrangement.

External links

Article
in

Organic Syntheses ''Organic Syntheses'' is a peer-reviewed scientific journal that was established in 1921. It publishes detailed and checked procedures for the synthesis of organic compounds. A unique feature of the review process is that all of the data and ex ...

: Org. Synth. 2007, 84, pp. 325–333.

References

{{Organic reactions Rearrangement reactions Name reactions