What is prochirality
- 1. What is Prochirality? Submitted to: Dr. Abida Submitted By: Sidra M.Phil. 1st Semester Session: 2020-2022 Course: CHM-533- Stereochemistry Department of Chemistry The Women University Multan
- 2. Term Prochirality: In stereochemistry, the prochirality meant for prochiral molecule that can be converted from achiral to chiral molecule. Thus, the achiral specie which can be changed in to achiral molecule is called prochiral and this conversion processes known as prochirality.
- 3. Notation of prochiral molecule: Prochiral molecules, prochiral carbon having same substituent are labeled by R and S notation for labeling of chiral centers. For example in ethanol the 2 hydrogen on prochiral center is designated as R and S. Explanation: Prochiral hydrogen’s can be designated either enantiotopic or diastereotopic. Enantiotopic H’s: If either HR or HS on ethanol were replaced by a deuterium, the two resulting isomers would be enantiomers (because there are no other stereo centers anywhere on the molecule). Thus these two hydrogen’s are enatiotopic.
- 4. Diasterotopic H’s: If either of the prochiral hydrogen’s HR or HS is replaced by a deuterium, a second chiral center is created, and the two resulting molecules will be diastereomers (one is S,R, one is R,R). Thus, in this molecule, HR and HS are referred to as diastereotopic hydrogen’s.
- 5. Homotopic H’s: Finally, hydrogen’s that can be designated neither enantiotopic nor diastereotopic are called homotopic. If homotopic hydrogen is replaced by deuterium, a chiral center is not created. The three hydrogen atoms on the methyl (CH3) group of ethanol (and on any methyl group) are homotopic.