1,2-Rearrangement

A reaction in which an atom or group migrates from one atom to an adjacent atom within a molecule, changing its connectivity.

Connect

Wagner–Meerwein rearrangement: A carbocation rearrangement in which a neighboring alkyl or hydrogen group migrates to the positively charged carbon. It is a classic 1,2-shift driven by formation of a more stable carbocation.
Organic reaction mechanism: A stepwise account of how bonds break and form during an organic chemical reaction. A 1,2-rearrangement is identified by tracing its bond changes.
Favorskii rearrangement: A base-promoted rearrangement of an α-haloketone that commonly produces a carboxylic acid derivative. Its ring-contraction and substitution pathways include a carbon-skeleton shift.
1,3-Rearrangement: A rearrangement in which an atom or group migrates between atoms separated by one intervening atom. Its migrating group spans a different distance than in a 1,2-shift.
Pinacol rearrangement: An acid-catalyzed conversion of a vicinal diol into a carbonyl compound by loss of water and a 1,2-migration. It shows how migration can accompany dehydration and carbonyl formation.
Skeletal formula: A shorthand drawing of an organic molecule in which lines represent bonds and vertices represent carbon atoms. It makes the neighboring atoms and migrating group visible.
Benzilic acid rearrangement: A base-induced conversion of a 1,2-diketone into an α-hydroxycarboxylic acid by a 1,2-aryl shift. It is a well-defined example of migration between adjacent carbon centers.
Sigmatropic rearrangement: A pericyclic reaction in which a sigma bond shifts across a conjugated π-electron system. It is classified by orbital reorganization rather than simple adjacency of migration endpoints.
Beckmann rearrangement: An acid-promoted conversion of an oxime into an amide by migration of a group from carbon to nitrogen. The migrating group’s position relative to the leaving group determines the product.
Curved-arrow notation: A notation that represents the movement of electron pairs in a chemical reaction. Arrows show how migration redistributes bonding electrons.