Stereochemistry Flashcards
Why does the 3-D shape of structures matter?
The 3-dimensional arrangement of atoms within organic compounds can cause dramatic changes in their properties.
Many molecules in living things have unique 3-dimensional arrangements, affecting their interactions.
What is the significance of 3TC in HIV treatment?
3TC interferes with viral DNA synthesis but does not affect human DNA, making it an effective HIV medication.
What tragedy is associated with thalidomide?
Thalidomide was linked to over 10,000 infants born with limb malformations after being introduced as a morning sickness treatment.
What are isomers?
Different compounds with the same molecular formula.
What are constitutional isomers?
Isomers with different atomic connectivity.
What are stereoisomers?
Isomers with the same atomic connectivity but with different 3-dimensional arrangements.
Define chirality.
Chirality is the ability of objects to exist as non-superposable mirror images of each other.
What distinguishes chiral from achiral objects?
Chiral objects cannot be superimposed with their mirror images; achiral objects can.
What is an example of a chiral molecule?
Chiral molecules are non-superimposable mirror images and do not possess a mirror plane.
What is an enantiomer?
Chiral molecules and their non-superimposable mirror images.
What properties do enantiomers share?
Enantiomers have identical physical and chemical properties, such as melting point and boiling point.
How can enantiomers be differentiated?
Enantiomers can be differentiated by interactions with other chiral molecules and optical activity.
What is optical rotation (α)?
The angle that a sample rotates plane-polarized light.
What is a racemic mixture?
A 1:1 mixture of two enantiomers that does not rotate polarized light.
How is chirality indicated?
Using absolute configuration denoted as R or S.
What are the Cahn-Ingold-Prelog Rules?
Rules used to assign priority to groups attached to a chirality center based on atomic number.
What is the maximum number of stereoisomers formula?
Maximum # stereoisomers = 2^n, where n = number of chirality centers.
What are meso compounds?
Molecules that can have chirality centers but are achiral due to an internal mirror plane.
Define diastereomers.
Stereoisomers that are non-superimposable and non-mirror images.
What is the difference between enantiomers and diastereomers?
Enantiomers change configuration at all stereocenters; diastereomers change configuration at some stereocenters.
What is the relationship between boiling point and diastereomers?
Diastereomers have different physical and chemical properties, including boiling point.
What is double bond isomerism?
A classification of alkenes based on the CIP rules, assigning E (trans) or Z (cis) configurations.
What is the difference between dextrorotary and levorotary?
Dextrorotary rotates polarized light clockwise (+); levorotary rotates it counterclockwise (−).
What is the significance of R-limonene and S-limonene?
R-limonene is found in citrus fruits, while S-limonene is found in lemongrass and smells like pine trees.
