Conjugated Diene Addition: 1,2 vs 1,4 Products (Kinetic vs Thermodynamic)

Understand electrophilic addition to conjugated dienes. Allylic carbocation resonance, 1,2 vs 1,4 products, and temperature control (kinetic vs thermodynamic).

• Reaction: Conjugated diene + HX → allylic halides
• What it does: Gives two regiochemical products (1,2 and 1,4)
• Typical reagents: HBr, HCl, etc.
• Key intermediate: Resonance-stabilized allylic carbocation
• Driving force: Stability of products + reversible steps at higher T
• Exam type: Kinetic vs thermodynamic
• Exam type: Regiochemistry
• Exam type: Predict product