Stereochemistry I
If a molecule has clockwise rotation via the Cahn-Prelog-Ingold rules, what letter would we use to designate the chiral center?
R
If a molecule has counter-clockwise rotation via the Cahn-Prelog-Ingold rules, what letter would we use to designate the chiral center?
S
What makes a better leaving group? Fluorine or Bromine?
Bromine
What kind of bond does an elimination reaction produce?
A pi bond. (Double or Triple Bond)
What has a larger atomic radius, Iodine or Bromine?
Iodine.
Z
What letter does the term "trans" go with?
E
Which of the substitution reactions is 1 step?
Sn2
What is the main difference between E1 and E2 reactions?
E1 produces a carbocation intermediate and E2 is concerted.
What is more stable Bromine Anion or Cl Anion? And why?
Bromine Anion is more stable because it has lower charge density, meaning it can spread its electrons more easily across its larger surface.
When drawing a fisher projection are all of the side substituents on wedges or dashes?
Wedges
What do you do if you are designating a molecule as R or S and the atoms you are looking at has hydrogen on a wedge?
You flip the answer.
What is the intermediate formed in Sn1 reactions?
Carbocation
What is the more stable product in an elimination reaction, the trans or cis product?
Give me an example of a stereocenter that is not a chiral center.
The carbon of an alkene that is E or Z.
What is the difference between a stereocenter and a chiral center?
All chiral centers are stereocenters, but not all stereocenters are chiral centers. Stereocenters are any atom, where if you swap the position of two atoms on it, adopts a different configuration. A chiral center is just carbon attached to 4 different things.
What is more stable, a molecule with the cis configuration or the trans configuration?
Trans
What makes a good leaving group?
A weak (stable) base.
What is the rate determining step in E1 reactions?
Formation of carbocation intermediate.
Does making bonds release or require energy?
Releases energy
In the chair conformation of 1,2-dimethylcyclohexane. Both groups are up but one is axial and one is equatorial. Is this molecule cis or trans?
Cis
What is a meso compound?
An achiral compound containing chiral centers. Another way of saying this could be a compound with chiral centers containing an internal mirror plane.
What is the term for all bond-breaking and bond-making happening in one step in Sn2 reactions?
Concerted
What happens faster E2 or E1 reactions?
E2
Does breaking bonds release or require energy?
Requires Energy