D.9.5+Drug+Design

** A chiral auxiliary is a "chiral molecule that is temporarily attached to a non-chiral molecule and directs the synthesis in a asymmetric manner so that only one enantiomer is formed".
 * D.9.5 Describe the use of chiral auxiliaries to form the desired enantiomer

This is useful as enantiomers have identical chemical properties in relation to non-chiral reagents and cannot therefore be easily chemically separated. However: the differences between the properties of enantiomers in biochemical reactions makes a separation vital as some enantiomers of certain drugs have adverse affects on the human body, while the other enantiomer has beneficial properties.

Once the required enantiomer has been made, the auxiliary can be removed and recycled.

(Note: The image above has been scanned and uploaded from the //IB Chemistry Study Guide// by Geoffrey Neuss)