The Smiles rearrangement is an intramolecular aromatic nucleophilic substitution reaction. It involves the migration of a substituent X from one carbon of an aromatic ring to another, with an aromatic substituent Y acting as the nucleophile. A specific example provided is the migration of an SO2Ar group to the ortho position of an ArO- nucleophile, activated by an adjacent nitro group. The X group is usually S, SO, or SO2, while the Y nucleophile is typically the conjugate base of OH, NH2, NHR or SH, though even CH2 has been used.

1. Reaction and Mechanism of
Smiles Rearrangement

2. SMILES REARRANGEMENT
Smiles rearrangement is intramolecular aromatic
nucleophillic substitution.

3. THE SMILES REARRANGEMENTS ACTUALLY COMPRISES A GROUP OF
REARRANGEMENTS THAT FOLLOW THE PATTERN GIVEN ABOVE. A SPECIFIC
EXAMPLE IS
In the given example SO2Ar is leaving group and ArO- is the nucleophile and
the nitro group serves to activate its ortho position. The ring at which the
substitution takes place is nearly always activated usually by ortho or para nitro
group.

4. X IS USUALLY S, SO, SO2. Y IS USUALLY THE CONJUGATE BASE OF OH,
NH2, NHR OR SH. THE REACTION HAS EVEN BEEN CARRIED OUT WITH
Y=CH2.