Recitation 4: Stereoisomerism 1. Indicate, with asterisks (*), all of the chiral centers in each of the following molecules (SLO 4.1). For each molecule, what is the maximum number of stereoisomers that can be formed? O
O H2N
H
HO
H
H
O
N H
O
O
O
2. For each chiral center, prioritize the groups (1 – 4) attached to each chiral center. Based on your priorities, assign R or S configurations to the chiral center (SLO 4.2). O OH
H H3CH2C
H H
CH3
Br
Cl H3CH2C
H 3C H3CH2C
H
Br H3CH2C
OH
H
CH3
3. Indicate the absolute configuration (R or S) of all stereocenters for the following molecules (SLO 4.2). Provide IUPAC names for the molecules. H a)
H 3C
Cl Cl CH2CH3
b)
H
CH3 Br H CH3
CH3
Cl Cl c)
d)
Cl
H
H
Br CH2OH