C9. Stereochemistry

Question 1

In the case of multiple stereogenic centres, how do you calculate the number of alternative configurations?

Answer 1

2 to the power of n: n is the number of stereogenic centres ONE NOTE

Question 2

What are diastereoisomers (diastereomers)?

Answer 2

Stereoisomers which are not enantiomers are called
diastereoisomers (diastereomers)

Question 3

enantiomer?

Answer 3

pairs of compounds with exactly the same connectivity but opposite 3D shapes e.g 1R 2S and 1S 2R

Question 4

How to draw an enantiomer?

Answer 4

draw exact mirror image or draw the groups in the opposite orientation ONE NOTE

Question 5

relationship between conformation and configuration?

Answer 5

change in conformation does not affect configuration

Question 6

diastereomer?

Answer 6

type of stereoisomer that is not another mirror image of another stereoisomer of the same compound e.g 1R 2S and 1R 2R or 1S 2S ONE NOTE

Question 7

what is a 2- epimer?

Answer 7

a sugar that differs from another sugar in the configuration at the second carbon atom e.g 1R 2S and 1R 1R

Question 8

what is a 1- epimer?

Answer 8

a sugar that differs from another sugar in the configuration at the first carbon atom e.g 1R 2S and 1S 1S ONE NOTE

Question 9

Describe the properties of enantiomers?

Answer 9

Enantiomers are chemically
identical except in optical
properties, e.g. (–)- and (+)-
ephedrine. Biological
properties may be different

Question 10

Describe properties of diastereoisomers

Answer 10

Diastereoisomers have
different physical and
chemical properties, e.g. (–)- ephedrine and (–)-
pseudoephedrine