Ch. 14 conjugated dienes

Question 1

properties of conjugated dienes

Answer 1

• Typical bond lengths
  C-C single 154 pm
  C-C double 131 pm

Question 2

Resonance Energy

Answer 2

• 4.1 kcal/mol

Question 3

H-X addition (1,2 &1,4)

Answer 3

-At low temp the 1,2 product is always the major product due to kinetic control. The reaction is considered irreversible and a fast reaction
- At high temperature the major product is usually the most stable alkene and is considered reversible at equilibrium

Question 4

EDG and EWG of dienes (MO theory)

Answer 4

• EWG: lowers the LUMO of the dienophile and EDG raises the HOMO of the diene causing the gap between them which allows the rxn to occur at lower temps