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46 Cards in this Set

  • Front
  • Back
What is a Nucleophile
Usually a Base, has lone pair or pairs of electrons. It attacks electrophiles
What is an electrophile?
Usually a carbon molecule that is attached to a LEAVING GROUP. usually has a carbon atom with a partial positive.
What is a Leaving Group?
a substituent that get displaced by a nucleophile. It is usually a WEAK BASE that comes from a strong acid.
What is the importance of solvents?

What are two types of solvents?
Give definition of each
it is the medium where most reactions occur.

polar protic: Can Hydrogen bond

polar aprotic: No Hydrogen bonding
What are the four KEY COMPONENTS you need to consider in distinguishing the differences between Sn2 and Sn1?
Nucleophile, Electrophile, Leaving group, and solvent
What does Sn2 stand for?
bimolecular nucleophilic substitution
What is the rate law equation of Sn2?
k[Nuc][Electro]=rxn rate
What is a concerted reaction?
It is an Sn2 reaction, which happens in one shot
Why does Sn2 always attack from the back?
because of molecular overlap and less electrostatic repulsion
If you have a stereo Center. what happens after an Sn2 reaction occurs?
What are the two key components of Nucleophility?
Basicity and Polarizability
What are the two key factors of a Leaving Group?
Basicity and Resonance
What is the trend of basicity in the nucleophile?
the more basic the base the stronger the nucleophile. Also base with a negative charge is a stronger base than without negative charge.
What is the trend on the periodic table for Nucleophility?
It increases from Right to left in the periodic table.

Example: -CH3 is better than -OH
What is Polarizability?
ability for molecule to reoirent electrons to one side of the atom to provide effective molecular orbital overlap
What is the trend in polarizability in the periodic table?
It increases from top to bottom.
What makes a good leaving group?
the weaker the base the better the LG b/c it can stabilize negative charge.

Conjugate base of a straong acid

(i.e. Br, I, Cl, but not F
lower the pKa the better the LG
Why is resonance important for a leaving group?
It will be more stable in its anionic form
(i.e. sulfate and sulfanate)
What does EE stand for?
enantiomer excess
What will you have when you have different proportions of an enantiomers?
Optically Active
what are the two properties that are different about enantiomers?
1) rotates polarized light equally but opposite

2) Interacts differently with other chiral molecules
What is it called when you have equal proportion of both enantiomers?
Racemic Mixture
What kind of mixture makes it optically INACTIVE?
racemic mixture
Name 2 rules for chirality
1) no plane of symmetry
2) chiral center
Steps for nomenclature
1) Longest chain
2) Lowest number for substituents
3) In alphabetical order

Remember: R & S
What is the preferred geometry?
Sp2 hybridized
For MOD, what is the importance of methane?
It might a be a new fuel source. Enough for the next 2000 years, but the problem is how to extract it. Maybe caused a mass extinction a long time ago.
What is Hammnd's postulate for an endothermic reaction?
For an endothermic reaction the transition state looks more like the products in the starting materials.

(i.e. the TS is late)
What is the character in a late transition state?
There is a radical character
What is rate determining step?
It is always the highest barrier Activation energy.
What is the condition for a termination process?
The concentration must be low in order for termination process to occur.
Why is a 2ndary radical more stable?
because of hyperconjuagation induction
What is the importance of the MOD Methyl bromide?
It comes from industry. It's a gas. Ozone depleting. It is used as a pesticide (primary strawberries). It is heavy and stays on the ground.
Does the more stable product most have the lowest AE leading to it?
Steps of Radical Halogenations
Calculate overall delta H

Draw reaction diagram- based on 1st and 2nd step either endo or exo

Know Activation energy

Know rate determining state

use Hammate post

arrow pushing
When looking for enantiomers it is important to remember this in a bond line structure...
remember that there is free rotation in some of the watch out!!!
What is the importance of esomeprazole (MOD)?
It it is prilosec. Problem is that for some people it doesn't work. R worked better than S in rats. S better in humans.
What is a psuedostereocenter?
It is a fake stereocenter. It might look like a stereocenter but in reality it is not.
What is a (+) rotation of light in clockwise direction called?
What is the (-) counterclockwise direction called?
Why can't silica gel separate chrial molecule?
Silica gel is not chiral
What is a hindered rotation called?
If you start with no optical activity what is the result?
You will end up with no optical activity
How can you predict a major form in a radical reaction?
When the readical is hindered by a big group such as a methyl in a 1,2-dimethylcyclopentane
what is the nucleophilicty prediction in the gas phase?
Why is a Flourine a horrible Nucleophile?
b/c it either does not dissolve or is wrapped up in polar protic solvent