A
1,2-rearrangement or
1,2-migration or
1,2-shift or
Whitmore 1,2-shift is an
organic reaction where a
substituent moves from one atom to another atom in a
chemical compound. In a 1,2 shift the movement involves two adjacent atoms but moves over larger distances are possible. In the example below the substituent R moves from carbon atom C
2 to C
3.