Organic Chemistry

Lecture 4: Molecular Orbitals and Aromaticity

Objectives and Skills

KEY INFORMATION SUMMARY


HERE you can find extra resources to help you with this lecture!

PROBLEMS

Problem 4.1: Benzene Properties
  1. Explain why we cannot use two Kekulé structures (alternating single-double C-C bonds of different lengths) to show benzene resonance. SOLUTION
  2. Draw the proper resonance structures for benzene. SOLUTION

If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the problem below ;)

Problem 4.2: Aromaticity

Assign the classification of aromatic, anti-aromatic, or non-aromatic to each of the structures below using Hückel’s Rule and check your classifications using the polygon method for p-system MO. SOLUTION
 

If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the problem below ;)

Problem 4.3: Polycyclics and Ring Shapes

Pentalene is unstable, even at -100°C, whereas heptalene can be made and is shown to react like a acyclic alkene. Explain the difference. SOLUTION


If you made some mistakes or want to practice more, review the concepts that gave you trouble and work on this extra problem. If you're good, move to the next lecture​​​​​​​ ;)

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