Atropisomers

These are exceptions to the rule: molecules that contain no chiral centers yet are chiral due to their inability to freely rotate.

Allenes

Imagine that the allene is a big double bond. If it is able to form E or Z isomers, it is chiral

Substituted Biphenyls

Must meet two criteria to be chiral:

  1. All substituents are in the ortho- position
  2. None of the rings have two of the same group on them

*ortho- is a term we will use in Organic Chem 2. It means “adjacent to”, basically that the groups next to the primary carbon linking the two rings.  

Example: Is the the following substituted biphenyl chiral?

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Example: Is the the following substituted biphenyl chiral?

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