Identify the correct reactivity order for the S _ N 2 reaction among the following compounds: (i) (ii) (iii)

Step-by-step solution

The reactivity of S _ N 2 reactions at the -position of heteroatoms depends on the polarizability of the heteroatom, steric factors, and ground-state stabilization. 1. Polarizability: Sulfur is larger and much more polarizable than oxygen. In the S _ N 2 transition state, the highly polarizable sulfur atom can better stabilize the partial charges and the electron-rich transition state compared to the less polarizable oxygen atom. This significantly lowers the activation energy for the reaction. 2. Anomeric Effect (