Question

Question 3 (1 point) What is the relationship between the following molecules? Br Br Same compound. Pair of enantiomers. Pair of diastereomers. Unrelated. Two of the above. Question 4 (1 point) Saved Which of the following molecules has stereogenic center with configurati Br

Answer 1

Question 3

(R) (3R,4R)-4-bromo-3-methylheptane (31,4R)-3-bromo-4-methylheptane The pair of molecules are not stereoisomers. So, they are unrelated.

Question 4

Br achiral achiral Br Br Br Br This structure has a stereogenic center with R configuration S-configuration

Question 5

Br The above pair of molecules are Enantiomers. So, a 50/50 mixture will result in an optically inactive pair of enantiomers.

R-S Nomenclature - Absolute configuration The designation of the absolute stereochemistry of any optically active compound according to this system involves the following steps: 1. A priority no such as (1). (2). (3) and (4) is assigned to each of the four atoms or groups of atoms attached to the chiral carbon n accordance with the following sequence rules. i. If the four substituent attached to the chiral carbon are all atoms, their priority no's. are decided on the basis of their atomic no's. The atom of higher atomic no. gets the higher priority. ii. If the relative priority of the two groups attached to the chiral carbon cannot be decided on the basis of above rule, it may be decided by comparing the atomic no's of the next atoms in the groups. ii. Each doubly bonded atom is duplicated and each triply bonded atoms is triplicated. 2. Once the order of the priorities of the four atoms or groups directly attached to the chiral carbon has been decided the molecule is then oriented in space in such a way that the group of lowest priority is directed away from us. Ifin going from 1+ 2+ 3, the eye moves in a clockwise direction, the configuration is specified as R and if in the anticlockwise direction, the configuration is S.