Summary
Summary Summaries CMY 127
- Course
- Institution
Summaries based off the textbook and class notes
[Show more]
1 review
By: ghostrhoda • 2 year ago
Seller
Follow
ath101
Reviews received
Content preview
THEME 3: STEREOCHEMISTRY: CHIRAL MOLECULESCHIRALITY (HANDEDNESS)
‐ Left- and right-hand mirror images of one another
‐ Mirror images not identical
‐ Mirror images are non-superimposable
‐ Objects and molecules that aren’t superimposable on their mirror images are said to
be chiral
‐ Some objects have mirror images that are identical (i.e. superimposable and achiral)
‐ These objects all have a plane of symmetry which means that half the object is a
mirror image of the other half
‐ Organic molecules that are not superimposable on their mirror images are said to be
chiral
‐ These molecules do not have an internal plane of symmetry in any of their
conformations
‐ The configuration of a molecule is its 3D arrangement of atoms that can only be
changed by breaking bonds
‐ These 2 molecules have a different configuration
ENANTIOMERS
‐ Chiral molecules are not the same as their mirror images
‐ A chiral molecule and its mirror images are a pair of enantiomers
‐ Chirality is most commonly due to the presence of a tetrahedral carbon atom
bonded to four different groups
‐ We call a carbon with four different groups bonded to it a stereo centre/chiral centre
FINDING STEREOCENTRES
‐ Look for a carbon with four different groups – may be different alkyl groups,
different functional groups etc.
‐ Divide the rings in half and check if they differ each different side counts as a group
in the ring
, DETERMINING IF A MOLECULE IS CHIRAL
‐ Imposable → achiral – do not fit on one another when mirror image
‐ Superimposable → chiral – when put mirror images on top of one another they line
up
‐ 2 conditions for molecule to be chiral:
➢ Presence of stereo genic centre
➢ No plane of symmetry in molecule
THE BIOLOGICAL IMPORTANCE OF CHIRALITY
‐ The binding specificity of a chiral receptor site for a chiral molecule is usually only
favourable in one way
‐ Chiral molecules are like hands and the receptors like gloves
NAMING ENANTIOMERS
‐ Because enantiomers are different compounds, each must have a different name
‐ The R, S system is a way to distinguish between enantiomers without having to draw
them and point to one another
THE R,S SYSTEM TO SPECIFY CONFIGURATION
‐ Specifying the configuration of a molecule as R or S is a way of describing the
complete structure of a molecule
1. Assign a priority from 1 (highest) to 4 (lowest) to each group bonded to the stereo
centre using the Cahn- Ingold-Prelog sequence rules
2. Orientate the molecule in space so that the group of lowest priority (4) is directed
away (dashed) away from you. The other 3 groups then project towards you
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller ath101. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $2.85. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
72042 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now