The document is a study guide for a chemistry exam covering various organic chemistry topics including allylic and conjugated systems, aromaticity, electrophilic aromatic substitution, carbonyl chemistry, amino acids, and peptide sequencing. It provides definitions, reaction mechanisms, and practice problems for key concepts that will be tested. The study guide emphasizes memorizing fundamental steps and rules for different reaction types as well as clearly indicating hybridizations and understanding how underlying concepts link various topics together. It concludes by recommending getting sufficient rest before the exam and trusting one's conceptual understanding of material to answer problems, even those involving unfamiliar reactions.
Chemistry Study Guide: Allylic Systems, Aromaticity, Carbonyls
1. Shashank Patil
Chem 3B Study Group
OH: W1-2PM/Th 10-2PM
shashankpatil@berkeley.edu
August 10, 2016
Worksheet 11: Final Review
1. Allylic Systems
a. What is an allylic system? ______________________________________
b. What type of property do allylic molecules exhibit?
____________________________________________________________
c. Identify all allylic carbons & hydrogens:
d. Allylic Bromination using ___________________________________
i. Show all monobromination products (assume cat. Br radical)
2. Conjugated Systems
a. What is a conjugated system? ______________________________________________________
b. What type of property do conjugated molecules exhibit?
c. How is this different from allylic molecules?
_____________________________________________________________________________________________
d. Diels Alder (Show all products):
i.
2. 3. Hybridizations in cyclic systems + Aromaticity: Each of the hetero-cycles below are
aromatic. Clearly indicate which atomic orbital (p, sp2, sp, etc.) each lone pair resides in.
a. Huckel’s rules: What properties do all aromatic molecules share?
i. ____________________
ii. ____________________
iii. ____________________
iv. ____________________
b. What’s the difference between anti-aromatic, non-aromatic, & aromatic
molecules?
c. Draw a Frost Diagram (inscribed polygon method) for molecule A.
4. Electrophilic Aromatic Substitution (EAS)
a. What are the 3 fundamental steps in ALL EAS reactions?
i. _________________
ii. _________________
iii. _________________
b. Friedel Crafts Alkylation: List 3 problems with this type of EAS
i. ____________________
ii. _____________________
iii. _____________________
c. Friedel Crafts Acylation (Mech.)
5. Diazzonium Ion (fill in missing reagents + final products)
a. Helps us form many substituted Benzenes!
3. 6. SNAR: Nucleophilic Aromatic Substitution
a. Remember that you need an Electron Withdrawing Group (“electron sink”) at
the __________ or __________ positions in order for this reaction to occur.
b. This reaction typical occurs in 2 steps
i. Addition of Strong Nucleophile (Rate determining step: dependent on
the electrophilicity of C)
ii. Leaving Group leaves by pushing electrons down from EWG.
c.
7. Carbonyl/Hydrate/Hemiacetal/Acetal Chemistry
a. Be comfortable interconverting between all of these intermediates
b. Why can’t we form an acetal from a carbonyl in basic conditions?
i. __________________________________________________________________
c. Why are acetals stable in basic conditions but are reactive in acidic
conditions?
i. ___________________________________________________________________
d. When we use a diol(or analogous structure) to react with a carbonyl to form
an acetal we say that we are ___________________ the carbonyl, using the diol as a
_____________________.
e. In the acetal we say that the carbon that used to be the carbonyl carbon is the
site of a __________________.
f. By exposing our acetal to acidic conditions (H3O+, H2O) we can _____________
our carbonyl.
g. Sugars “-oses”= hemiacetal chemistry
i. Anomeric carbon: The site of a hidden _____________
ii. If the anomeric hydroxyl is facing up it is a(n) _________ anomer and if
the anomeric hydroxyl is facing down it is a(n) __________ anomer.
iii. Recall types of glycosidic linkages
8. Alpha & Beta Carbon Chemistry
a. Enol/Enolates can be converted into their keto (or carbonyl form) via _______
b. Enolate Alkylation
c. Aldol addition: When an enol/enolate attacks another carbonyl to yield a
_________________
4. d. Aldol Condensation always creates a _____________________________
e. We can react with this molecule in one of two ways depending on our
nucleophile. What two positions can we nucleophillically attack? __________
f. What nucleophiles attack 1,2 and what nucleophiles attack 1,4? List as many
as you can think of
i. 1,2:______________________________________________________________
ii. 1,4: _____________________________________________________________
g. What is the kinetic product and thermodynamic product refer to when
discussing reactivity of these molecules? (Explain in your own words and use
an energy diagram )
h. Robinson Annulation is a combination of _______________________ + _______________
i. (Remember the differences between RA in ketones vs. esters)
9. Carboxylic Acid Derivatives
a. Name all of the CAD’s and list them in order of decreasing reactivity:
i. _________________________________________________________________________
b. We’ve spent a lot of time on esters so let’s do some anhydride reactivity:
c. Amides
i. Lithiates
5. ii. Reduction
10.Fatty Acid Synthesis
a. We activate _______________ to get _______________.
i. We activate this molecule by ________________________
b. Malonyl CoA gets _________________ to from the enolate form of ______________
c. This enolate attacks our growing fatty acid chain
d. Enzymes 3 & 4 remove the _________________
e. Repeat steps 1-4 to continue adding _____ carbons at a time to our growing
fatty acid chain.
f. To have our fatty acid in its completed form we finally need to do ____________
g. What CAD is a Fatty acid?
11.Amino Acids
a. Amino acids are linked together via _____________ to make ______________
b. In physiological conditions, amino acids usually exist as ____________
i. pKa amino group:
ii. pKa carboxylic acid:
c. Sequence the octapeptide(on the back) with the following information.
Enzyme Cleaves Amino acids
Trypsin Carboxy side ofbasic amino acids Arg, Lys
Chymotrypsin Carboxy side ofhydrophobic aromatic amino acids Phe, Trp, Tyr
Thermolysin Amino side ofhydrophobic nonaromatic amino
acids
Val, Leu, Ile
6. Shashank’s Final Pointers:
#1: Get enough sleep. Pete’s going to Pete. Expect integration of concepts +
unfamiliar rxns/problems that are based upon conceptual understanding of
material. AKA you’ll need all the brain power you have at your disposal.
#2: Remember Stereoisomers!
#3: Trust yourself. You know this. All explanations & why’s can be answered with
just a few underlying concepts (e.g. resonance, electronegativity, coulombic
attraction/repulsion, sterics, aromaticity). I believe in you all!
Pep8 Pep4
Pep4
Exp 1 TAH
Asp, Lys, Ser, Leu
Gly, Asp, Val, +NH4
Why are there only three amino acid residues when we hydrolyze the second tetrapeptide?
Exp 2
Pep8
Hydrazine Val-NHNH2
Ser-NHNH2
Asp-NHNH2
Gly-NHNH2
Cys-NHNH2
Leu-NHNH2
Asn-NHNH2
Lys-NHNH2
Can you tell what the C-terminus amino acid is based on this? If so, what is the residue?
Exp 3
Pep8
1. Sanger's Reagent
2. 6M HCl,
H3O+, H2O
Sanger-Ser
Gly
Leu
+NH4
Val
Lys
2 Asp
Exp 4
Pep8
Thermolysin Ser
Pep4
Pep3
TAH
Lys, Asp, Leu, Gly
Val, Asp, +NH4
____ ____ ____ ____ ____ ____ ____ ____N- -C
What is the source of the ammonium ion?