Lecture Notes: Newman Projections in Organic Chemistry

Introduction

• Lecturer: Victor, Organic Chemistry Tutor
• Focus: Drawing Newman Projections for various molecules.

Approach to Drawing Newman Projections

• Orientation Technique:
  • Imagine standing in front of the molecule.
  • Use your body orientation to visualize the molecule.

Example 1

• Molecule Structure:
  • Front atom: Propyl group (down), Chlorine (right-up), Hydrogen (left).
  • Back atom: OH group (down), two implicit Hydrogens (wedge & dash).
• Confirmation:
  • Initial: Eclipsed with line as "Horizon".
  • Conversion: Rotate back atom to staggered conformation for stability.

Example 2

• Molecule Structure:
  • Front atom: CH3 (down), Hydrogen (right), O group (left).
  • Back atom: CH3 group, implicit Hydrogens.
• Confirmation:
  • Initial: Eclipsed.
  • Conversion: Rotate back atom by 180° for a staggered conformation.

Example 3 - Cyclic Molecule

• Molecule Structure:
  • Front Atom: CH2 (up, green), Chlorine (right), implicit Hydrogen (left).
  • Back Atom: CH2 (up, orange), CH3 (left), implicit Hydrogen.
  • Additional: Pink CH2 connects front and back atoms.
• Confirmation:
  • Rotate back atom by 60° for stabilization.

Example 4

• Molecule Structure:
  • Front Atom: Double-bond group (right), CH3 (left-up), implicit Hydrogen (bottom-left).
  • Back Atom: CH3, O group, implicit Hydrogen.
• Confirmation:
  • Conversion to staggered conformation by rotating back atom.

Example 5

• Molecule Structure:
  • Front Atom: Hydrogen (right), CH3 (left), three-carbon chain (bottom).
  • Back Atom: CH2-Ph group with CH3 (right) and Hydrogen (left-bottom).
• Confirmation:
  • Already staggered with bulky groups anti to each other.

Example 6 - Another Cyclic Molecule

• Structure:
  • Front Atom: Chlorine, CH2, implicit Hydrogen.
  • Back Atom: Chlorine (left), implicit Hydrogen (wedge), CH2.
• Connection:
  • Pink group connects green and orange CH2s.
• Rotation:
  • Rotate back atom by 60° clockwise.

Example 7 - Chair Conformation

• Process: Convert Chair to Newman Projection
  • Draw chair and identify positions.
  • Convert to Newman projection by focusing on bonds between selected atoms.

Example 8

• Molecule Structure:
  • Front Atom: CH3 (down), CH3 (left), implicit Hydrogen (right).
  • Back Atom: Ethyl group (up), O group (right), implicit Hydrogen (left-bottom).
• Confirmation:
  • Already in staggered conformation.

Example 9

• Viewing from Below
  • Front Atom: Ethyl (right), Chlorine (left-up), CH3 (down-left).
  • Back Atom: CH3 (plane with Ethyl), O (top-right), implicit Hydrogen (bottom-right).
• Re-draw:
  • Adjust positions for classic Pi or Y-shaped Newman drawing.

Conclusion

• Victor encourages engagement by liking and sharing if the walkthrough is helpful.
• Emphasizes practice and familiarization with drawing different projections and confirmations.