Zaitsev vs Hofmann: How to Predict the Major Alkene
Learn when elimination gives the Zaitsev vs Hofmann alkene. Includes base size, leaving group effects, quaternary ammonium exceptions, and practice problems.
Zaitsev default: More substituted alkene usually major (thermodynamic stability).
Hofmann triggers: Bulky base (t‑BuO⁻), poor leaving group contexts, quaternary ammonium (Hofmann elimination), steric/geometry constraints.
Mechanism context: Applies mainly to E2 (and sometimes E1 under thermodynamic control).
Cyclohexanes: Geometry can override substitution (only trans-diaxial β‑H counts).