Organic Chemistry - Iv - Stereochemistry

Front 1

Define stereoisomers.

Back 1

Two molecules that must have identical atoms and connectivity. They differ in the spatial configuration of their atoms. They could either be enantiomer or diastereomer.

Front 2

Define enantiomers.

Back 2

Enantiomers are nonsuperimposable mirror images of each other. Their difference lies in the orientation of atoms at one carbon.

Front 3

Define diastereomers.

Back 3

They are not mirror images of each other. They differ in the orientation of atoms at two or more carbons.

Front 4

What is the formula to find the possible stereoisomers?

Back 4

Find the number of number of chiral centers, then use the following formula to find the number of possible diastereomers that exist for that molecule: number of diastereomers = 2^n.

Front 5

How do you assign absolute configuration using the R/S system?

Back 5

Number the four different groups on the chiral carbon as 1,2,3 and 4 according to priority. 1 highest, 4 lowest.
Rules:
The higher the atomic number of this atom, the greater the priority of the group (connected to the chiral carbon)
If double of triple bonds exist, the atoms bonded are considered to be doubled or tripled in atomic number.
The lowest group, is usually placed in the back.
If the sequence is 1,2,3 clockwise, the molecule is designated as R; if counterclockwise it is S.