Question

In the box below draw the tetrahedral representation of the s enantiomer of the amino acid valine, ch3ch(ch3)ch(nh2)co2h.

Answer 1

The S-Enantiomer of Valine is attached below.

Assigning S-Configuration:

In Valine there is only one chiral carbon (carbon to which all bonded atoms or group of atoms attached have different masses). This carbon also known as alpha carbon has a tetrahedral geometry. For S-configuration, according to Cahn Ingold Prelog Rules the -NH₂ group is assigned with priority order of 1, The carbon of carboxylic acid is assigned the number two and the tertiary carbon is assigned with number three. These three groups are made in such a way that moving from number 1 to number 3 makes a S sign or anticlockwise rotation while keeping the hydrogen atom behind the plane.