Naming Enantiomers

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Naming Enantiomers


Lecture number:
15
Pages:
2
Type:
Lecture Note
School:
North Carolina State University
Course:
Ch 220 - Introductory Organic Chemistry
Edition:
1

Unformatted text preview:

CH 220 1st Edition Lecture 15 Outline of Current Lecture I. Stereochemistry at tetrahedral centers – enantiomers II. Naming enantiomers Current Lecture I. Stereochemistry at tetrahedral centers – enantiomers Molecules that have 1 carbon and 4 different substituents have a non-superimposable mirror image – enantiomers Such carbon atoms are stereocenters or chiral molecules CHXYZ This results in right and left hand versions First discovered by Louis Pasteur II. Naming enantiomers Uses priority system, like EZ 1. Rank 4 different substituents by atomic number and build with model kit 2. Hold the lowest priority substituent facing away from you and look at the remaining 3 groups on a plane 3. If the priorities 1,2,3 are clockwise then it is designated R (right) 4. If the priorities 1,2,3 are counter-clockwise then it is designated S (left) 5. If a decision cannot be reached by ranking the first atoms in the substituents, look at the second, third or fourth until there is a difference You should always build the molecule to making it easier to figure out designation (R or S) put a blue substituent on 1st priority, red on 2nd priority, yellow on 3rd priority and white on 4th priority. Once you have built it by looking at the diagram given, hold the white substituent away from you and look at the remaining three colors to assess. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.



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