Figure ‑ 2.. PES of the S N 2 and S N 1 mechanism

Elimination Elimination: One molecule is cleavaged into two molecule PT: Proton Transfer, LGE: Leaving Group Explusion Mechanisms E1 : leaving group (X) cleavage first) E2 : The H and the X is cleavaging simultaneously E1cb : H cleaved first (cb: conjugated base) The elimination reactions are often competing with substitution because of tight similarity

SN2SN2 1,2 E Compiting reaction ways A schematic illustration of two extreme cases: E2 is favoured over E1 (left hand side) and E1 is favoured over E2 (right hand side). It is assumed that under ordinary circumstances E1 cb is the least favoured mechanism.