SN2 Mechanism: Backside Attack, Transition State, and Inversion
Learn the SN2 mechanism step-by-step: backside attack, transition state, inversion of configuration, and how solvent/substrate control rate. Includes practice + common traps.
Key idea: One concerted step; no carbocation, no rearrangements.
Best substrates: Methyl, 1° > 2° (unhindered); 3° does not work
Best nucleophiles: Strong, often negatively charged (I⁻, RS⁻, CN⁻, N3⁻, HO⁻/RO⁻)
Best solvents: Polar aprotic (DMSO, DMF, acetone, MeCN)