Question

Indicate the stereochemical configuration for the tetrahedral centers shown below. 

Answer 1

Concepts and reason

This problem is based on the concept of absolute configuration.

Absolute configuration is used to represent the spatial arrangement of groups or atoms in a chiral molecule. Stereochemical descriptors which are used to represent the absolute configuration are R and S which refer to Rectus and Sinister.

Fundamentals

Assigning the R, S configuration involves some rules:

1.Assign the priority order to the groups or atoms.

2.The least prior group should be present at vertical positions. Count the priority number in increasing order from 1 to 3. If the order turns out to be clockwise then its R configuration and if it is anticlockwise then the configuration is S.

3.In case the least prior group is present at horizontal positions. Clockwise order is assigned as S and anticlockwise is assigned as R.

Priority order is assigned on the basis of atomic number, any group or atom having the highest atomic number will be the most prior group or atom.

Count the priority order from 1 to 3 to determine the absolute configuration.

Priority order is assigned on the basis of atomic number, any group or atom having the highest atomic number will be the most prior group or atom.

Count the priority order from 1 to 3 to determine the absolute configuration.

Ans:

The absolute configuration of the given compound is,

The absolute configuration of the given compound is,

Answer 2