1. The Hofmann Elimination

2. a quaternary ammonium hydroxide is the reactant and an alkene is the product is an anti elimination the leaving group is a trialkylamine the regioselectivity is opposite to the Zaitsev rule.

3. Quaternary Ammonium Hydroxides Ag 2 O H 2 O, CH 3 OH CH 2 N(CH 3 ) 3 + HO – are prepared by treating quaternary ammmonium halides with moist silver oxide CH 2 N(CH 3 ) 3 I–

4. The Hofmann Elimination 160°C CH 2 N(CH 3 ) 3 + HO – on being heated, quaternary ammonium hydroxides undergo elimination CH 2 (69%) + N(CH 3 ) 3 + H2OH2OH2OH2O

5. MechanismMechanism H CH2CH2CH2CH2+ –O H OH H N(CH 3 ) 3 CH2CH2CH2CH2

6. RegioselectivityRegioselectivityheat Elimination occurs in the direction that gives the less-substituted double bond. This is called the Hofmann rule. N(CH 3 ) 3 + HO – CH 3 CHCH 2 CH 3 H2CH2CH2CH2C CHCH 2 CH 3 CH 3 CH CHCH 3 + (95%) (5%)

7. RegioselectivityRegioselectivity Steric factors seem to control the regioselectivity. The transition state that leads to 1-butene is less crowded than the one leading to cis or trans-2-butene.

8. RegioselectivityRegioselectivity N(CH 3 ) 3 + HHH H CH 3 CH 2 C H CHH largest group is between two H atoms major product

9. RegioselectivityRegioselectivity N(CH 3 ) 3 +H H H CH 3 C H C H largest group is between an H atom and a methyl group minor product CH 3