Stereochemistry and Conformational Analysis

40 lessons, pages 3381–3420.

  1. Why Three-Dimensional Structure Matters — Same formula and connectivity, different shapes and behaviour
  2. Classifying Isomers: A Stereochemical Map — Constitutional isomers versus stereoisomers, configuration versus conformation
  3. Chirality and Mirror Images — Non-superimposable mirror images and the handedness of molecules
  4. Stereocentres and Stereogenic Units — Recognising carbon atoms with four different groups and other stereogenic elements
  5. Symmetry Elements and Achirality — Mirror planes, centres of inversion and why they cancel chirality
  6. The Cahn-Ingold-Prelog Priority Rules — Ranking substituents by atomic number and exploring outward
  7. CIP Rules for Multiple Bonds and Isotopes — Duplicate atoms for double and triple bonds; mass number as a tiebreaker
  8. Assigning R and S Configurations — Orienting the lowest priority group away and tracing 1-2-3
  9. R and S from Wedge-and-Dash Drawings — Handling the lowest priority group on a wedge, in the plane or on a dash
  10. Enantiomers and Their Properties — Identical physical properties except interaction with chiral influences
  11. Optical Activity and Specific Rotation — Plane-polarised light, polarimetry and the specific rotation equation
  12. Racemic Mixtures and Enantiomeric Excess — Optical purity, ee calculations and why racemates are optically inactive
  13. Molecules with Two Stereocentres: Diastereomers — The 2^n rule and stereoisomers that are not mirror images
  14. Meso Compounds — Achiral molecules with stereocentres and internal mirror planes
  15. Fischer Projections: Drawing and Reading — Horizontal bonds towards the viewer, vertical bonds away
  16. Manipulating Fischer Projections — Allowed rotations, forbidden moves and assigning R/S directly
  17. D and L Nomenclature for Sugars and Amino Acids — Glyceraldehyde as reference and how D/L relates to R/S
  18. Resolution of Racemic Mixtures — Separating enantiomers via diastereomeric salts and chiral chromatography
  19. Geometric Isomerism and Restricted Rotation — Why C=C double bonds and rings lock substituents in place
  20. Cis-Trans Naming and Its Limits — When cis and trans work and when they become ambiguous
  21. The E/Z System for Alkenes — Applying CIP priorities at each end of a double bond
  22. Properties of E and Z Isomers — Differences in dipole moment, boiling point, melting point and stability
  23. Molecules with Stereocentres and Double Bonds — Combining R/S and E/Z descriptors in full names
  24. Conformations and Rotation about Single Bonds — Sigma bond rotation, conformers and why they interconvert rapidly
  25. Newman Projections: Drawing Ethane — Front and back carbons, staggered and eclipsed forms, dihedral angles
  26. Torsional Strain and the Energy Profile of Ethane — The 12 kJ/mol rotational barrier and plotting energy against dihedral angle
  27. Conformational Analysis of Butane — Anti, gauche, eclipsed and fully eclipsed conformers and steric strain
  28. Converting Between Newman, Sawhorse and Fischer Views — Translating stereochemical information between representations
  29. Ring Strain in Cycloalkanes — Angle strain, torsional strain and heats of combustion per CH₂
  30. The Chair Conformation of Cyclohexane — Strain-free geometry, tetrahedral angles and staggered bonds
  31. Axial and Equatorial Positions — Drawing a chair correctly and locating the two sets of bonds
  32. Ring Flipping and Other Cyclohexane Conformers — Chair interconversion via half-chair, twist-boat and boat forms
  33. Monosubstituted Cyclohexanes and 1,3-Diaxial Interactions — Why substituents prefer equatorial positions; A-values
  34. Disubstituted Cyclohexanes: Cis and Trans — 1,2-, 1,3- and 1,4-patterns and finding the most stable chair
  35. Conformational Locking and Fused Rings — tert-Butyl anchors, cis- and trans-decalin and steroid frameworks
  36. Stereochemistry and Reaction Outcomes — Inversion in SN2, racemisation in SN1 and anti-periplanar E2 elimination
  37. Chirality Without Stereocentres — Axial chirality in allenes and biaryls, and atropisomerism
  38. Stereochemistry in Biology and Medicine — Enzymes, receptors, thalidomide and single-enantiomer drugs
  39. Solving Multi-Step Stereochemistry Problems — Combining R/S, E/Z, projections and chair analysis in one question
  40. Stereochemistry and Conformational Analysis: Unit Review — Key ideas, representations and exam strategies across the unit