Name: Diastereomers and Meso Compounds
Uploaded: 2019-07-19
Duration: 10 min 31 s
Description: Here, we will see how compounds with multiple stereocenters may be achiral if they have an internal plane of symmetry or an inversion centre. Let's explore.

Question

What does $D / L$ $&$ $d / l$ represent?

Accepted Answer

$D / L$ represents nomenclature (relative configuration) while $d / l$ represents the direction of optical rotation.

An optical isomer can be named by the spatial configuration of its atoms. The $D / L$ system (named after Latin dexter and laevus, right, and left), not to be confused with the $d -$ and $l -$ system.

This approach labels each chiral center $R$ or $S$ according to a system by which its substituents are each assigned a priority, according to the Cahn–Ingold–Prelog priority rules $(CIP Rule)$ , based on atomic number. When the center is oriented so that the lowest-priority substituent of the four is pointed away from the viewer, the viewer will then see two possibilities: if the priority of the remaining three substituents decreases in clockwise direction, it is labelled $R$ (for Rectus, Latin for right); if it decreases in a counterclockwise direction, it is $S$ (for Sinister, Latin for left).

An enantiomer can be named by the direction in which it rotates the plane of polarized light. Clockwise rotation of the light travelling towards the viewer is labelled $(+)$ enantiomer. Its mirror image is labelled $(-)$ . The $(+)$ and $(-)$ isomers have been also termed $d -$ and $l -$ (for dextrorotatory and levorotatory)

What does $D / L$ $&$ $d / l$ represent?

Important Questions on Organic Chemistry- Some Basic Principles and Techniques

Learn and Prepare for any exam you want !

What does D/L & d/l represent?

Important Questions on Organic Chemistry- Some Basic Principles and Techniques

Learn and Prepare for any exam you want !

What does $D / L$ $&$ $d / l$ represent?