What email address or phone number would you like to use to sign in to Docs.com?
If you already have an account that you use with Office or other Microsoft services, enter it here.
Or sign in with:
Signing in allows you to download and like content, and it provides the authors analytical data about your interactions with their content.
Embed code for: Ochem 326 SI 10 (Exam 2 Review) Chapters
Select a size
Organic Chemistry 326 SI
October 5th, 2016
READ the book or the note
Use Tables and Diagrams
Khanacademy.org (Free and useful for all classes!)
Review your assingments/quizzes
How are these molecules related?
None (compounds aren’t related)
How are these compounds related?
None of the above
Which molecule is a meso compound?
How may stereoisomers does this molecule have?
Name this compound.
Label the stereogenic centers
S, R, R
How many stereoisomers does this molecule have?
Which compound has a S configuration?
I and II
II and III
Which of the following statements about bond breaking is true?
Homolysis and heterolysis require energy.
In homolysis, the electrons in the bond are divided unequally.
In heterolysis, the electrons in the bond are divided equally.
Homolysis generates charged intermediates
Which of the following statements is not true?
Bond breaking is endothermic.
The bond dissociation energy for bond breaking is always negative.
Bond making is exothermic.
The bond dissociation energy for bond formation is always negative.
What is the name given to the minimum amount of energy required to complete a step?
Gibbs Free energy
Energy of activation
Transition state energy
CH3CH2CH2Br + KOH
None of these
What type of reaction is this?
Which of these molecules have a nucleophilic carbon?
Which step is the rate determining step?
1 and 2
2 and 3
Which mechanism shows the first step of the addition of HBr to and alkene?
Which radical is the most stable?
All are equally unstable
Which compound would form the most stable carbocation after protonation?
They would all be equally stable
What is the product?
Which starting material would be used to form this compound? (Reagent used: HBr)
Both A and B
None of these.
Which of these would form the most stable carbocation when reacting with KI / H3PO4?
All would react at the same rate
Not enough information.
Which statement is true?
1,2-hydride shifts are considered addition reactions
During these reactions, either a carbanion or hydride can shift
A hydride shift can only occur on adjacent carbons
I and III
What is the major product?
Which statement does not describe Markovnikov’s Rule regarding electrophilic addition reactions?
When HX is added, the more highly substituent carbocation will form
When HX is added, the hydrogen bonds to the more highly substituent carbon
This rule is a guide used to determine the regiochemistry of the reaction.
The less substituent carbon will be protonated when the pi bond breaks
Chapter 7 Reagents
(X = Br, Cl, I)
Alkyl halide (R-X) –
Halogen will add to the more substituted carbon
Protonation results in carbocation (rearrangement).
Markovnikov’s rule is followed (regiospecific)
KI / H3PO4
Similar mechanism to HI reagent.
Alkyl iodide (R-I) –
Iodine will add to the more substituted carbon
H2O / H2SO4
Alcohol (R-OH) -
Hydroxyl group (-OH) is added to the more substituted carbon
Which statement is true about elimination reactions?
Elimination reactions have 2 pi bonds breaking and 1 sigma bond forming.
Elimination reactions are always regioselective (will only form 1 product).
Dehydrohalogenation involves the removal of a halogen and a hydrogen
All are true
How many products may form when this molecule is reacted with H2SO4, H2O / THF, 50˙C?
What important intermediate forms during alkene bromination?
Anti dibromo compound
What is the name of the product?
Haloene (Halogen + Alkene)
What is the product called?
What is the name of this reaction?
Extra Material for Chapters 7 and 8
X = Cl, Br, or I
• Two Steps
• Carbocation forms
Syn and Anti
Hydration by Oxymercuration
• Three steps
• Acid Catalyzed
Syn and anti
1. Hg(OAc)2 , H2O/THF 2. NaBH4
• No carbocations form
• Mercurium ion forms
Alcohol forms on the more substituted carbon.
X2 X = Cl or Br
• Two steps
• Forms a bridged halonium ion
X2 / H2O
X = Cl or Br
• Three Steps
• X is bonded to the less substituted
• OH bonded to the more substituted carbon
NBS in DMSO and H2O
Hydroboration – Oxidation
Forms a Bromohydrin
 BH3 or 9-BBN
 H2O2, HO-
• Hydroboration is One step (box like structure)
• H bonds to more substituted
• OH bonds to the less substituted carbon
In the addition of HX to an unsymmetrical alkene, the H atom bonds to the less substituted carbon atom.
Occurs with HCl, HBr, or HI
Mechanism Two Steps:
1. Protonation of pi bond
Proton bonds to the more substituted carbon and forms the more stable carbocation
Follows Markovnikov’s Rule
2. Nucleophilic attack (-X)
Carbocation is what conformation?
Where will it be attacked from?
Top or bottom
Therefore the addition is both syn or anti!
If there is a stereogenic center, what forms?
HX Mechanism (HBr)
*If there is a stereogenic center forming at the carbocation, what forms?
What forms if we have 2 stereogenic centers?
What relationship does A and B have?? => diastereomers
What is(are) the product(s)?
I and IV
III and IV
According to Markovnikov’s Rule, when hydrochloric acid is added to 2-methyl-2-pentene, which product will form?
Very similar to HX
1. Protonation of alkene
Markovnikov’s Rule followed
2. Nucleophilic attack
What is the Nucleophile?? => H2O
3. Deprotonation of Oxygen reforms H2SO4
What does H2SO4 act as?
Hydration by Oxymercuration-demercuation procedure:
1. Hg is attacked by the pi bond electrons, and an OAc (CH3CO2 group) leaves to form a mercurium ion
2. Water attacks the more substituted carbon and deprotonation forms the –OH.
3. NaBH4 losses a hydride (H-) and it attacks the carbon bonded to the mercury which leaves
Essentially this forms an Alcohol bonded to the more substituted carbon.
What are the products?
II and IV
Which molecule forms?
What halogens can be used?
Br2 and Cl2
Why can halogens go through this reaction?
They are polarizable!
One can be slightly positive <= interacts with the alkene
One can be slightly negative
1. Addition of the slightly positive halogen
What does this form?
Bridged halonium ion
2. Nucleophilic attack by the other halogen
How do they add?
Forms racemic mixture
 H2O2, -OH
Which alkene addition reaction will not have a carbocation intermediate?
All of these reactions will form a carbocation intermediate
During an alkene addition reaction, which reagent will have a carbocation intermediate form?
Addition of Br2
Addition of BH3 and H2O2, -OH
Addition of an H2O in the presence of H2SO4
Addition of Cl2 and H2O
What is the classification of the product of this reaction?
What type of addition occurs in a Hydroboration-oxidation reaction?
Syn and Anti addition
End – Good Luck!!apter 8)
According to Markovnikov’s Rule, when hydrochloric acid is added to 2-methyl-2-pentene,