Microsoft Word - CS 2 Fa20 Masters.docx
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
1
Please upload this completed CS on Sunday, October 25 by
11:59 pm to Canvas. To do so, go to “Assignments” on Canvas
and click on the Case Study 2 assignment. Here, you will be
able to upload one pdf file.
This case study is worth 100 points. You are allowed to use
your class materials and your CHEM 202 textbook. You will
need to reference your class notes, ex: Unit 2 –
Saponification pp 25-28 and draw examples.
You may work with another student. If so:
o Please fill out both students’ info in the table above.
o Each team member must upload one copy. Remember,
you can work together via Zoom since each of you have
your own Zoom meeting room. Use a Google Jamboard
or the Zoom Whiteboard to work out the problems
during your virtual meetings.
o If you worked with a partner on this first case study, you
are not obligated to work with that partner again in the
future. It’s your choice!
o You can only work with one other student from our
section (only Dr. Masters’ section of CHEM 202).
Only use the space provided for your answers! Do not add
pages, use the back of the page, etc. Write concisely and neatly!
Here are ways to complete and submit this assignment:
1. Print out this case study, hand-draw your answers,
scan it*, and upload as a pdf to Canvas.
2. If you do not have a printer, write your answers on
lank sheets of paper. Please set up the pages as you
see here: landscape orientation, two columns: “Main
Questions” and “Supporting Questions”. Scan and
upload as a pdf file to Canvas.
3. Use your tablet to complete it electronically using a
stylus. Upload the electronic pdf file to Canvas.
*You can use the apps Camscanner or Scannable for scanning
documents using your phone. If you have an iPhone, you can
use the “Notes” app to generate a pdf file. You must generate
one pdf file for submission. It is your responsibility to
make sure your submissions are complete and legible.
Missing/illegible parts to the assignment will receive no
credit and will not be accepted late.
Academic Integrity & Honor Code. By providing your
signature, you are agreeing to not using any outside help (e.g.
Chegg or the like) or getting help from anyone outside of this
class. If this code is violated, a zero grade is earned.
_______________________________________________________________________
Signature
If you do not provide your signature, you will earn a zero.
Student Name(s) Access ID
(e.g. kmm14)
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
2
FOCUS OF CASE STUDY 2: A Synthetic Scavenger Hunt!
In this Scavenger Hunt, you will investigate a
synthetic scheme:
• To rationalize certain reaction outcomes
• To predict specified reaction outcomes
• To evaluate structures, plus more!
Take a look at the synthetic scheme. Here’s
some important observations about this
scheme:
• Starts with one reactant
• This one reactant can be converted to an
unknown compound, which you will
discover!
• The unknown compound can be used in two
different transformation pathways.
Your task is to discover the structure of the unknown compound and what needs to be done to complete
oth transformations, plus some other fun things to show-off your knowledge and understanding!
O
O
O Start here!
O
OH
OOH OH
O
OOH
steps steps
Can we do more?
?
An unknown compound
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
3
Question 1: STEP A!
GOAL of Question 1: Determine if compound 2 or
compound 3 is the prefe
ed product of STEP A.
Let’s start this scavenger hunt by answering scavenger
questions. Your answers to the scavenger questions will achieve
the GOAL of this question!
SCAVENGER QUESTIONS:
Q1(a). List the two functional groups in compound 1: ________________________ and ________________________ (2 pts)
Q1(b). Describe what is changing in compound 1 to become compound 2 or compound 3. (3 pts)
Q1(c). Label the two alpha (a) ca
ons with the a symbol in the structure on the right
(compound 1), then draw in the Hs on these alpha ca
ons. (3 pts)
Q1(d). Which alpha (a) hydrogen is most acidic? Justify your answer with structures and words; use your in-class notes as a
eference as well. (6 pts)
O
O
O
NaOEt, CH3B
O
O
O
O
O
O
1
2
3
o
STEP A
O
O
O
1
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
4
Q1(e). The function of NaOEt (Et = CH2CH3) is a _______________, which ( protonates / deprotonates ) the most acidic alpha
H in compound 1 to generate an ________________________ nucleophile. (3 pts)
Q1(f). Given your answer to part (e), the function of CH3Br is the _______________________________. Provide a
ief explanation. (4 pts)
DIGGING DEEPER QUESTIONS
Q1(g). Circle all chiral centers in compounds 2 and 3. (3 pts)
Q1(h). Draw the enantiomers of compound 2 (4 pts) in the empty box below and determine
the R or S configuration of each chiral center in your enantiomers (4 pts).
O
O
O O
O
O
2 3
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
5
Questions 2 & 3: STEPS B & C!
GOALS for Question 2:
Determine:
• the structure of compound 4
(the other reactant of STEP B).
• the structure of compound 5.
• the complete mechanism of
STEP B.
Q2(a). In an aldol addition reaction, the electrophile is a ___________________ or _____________________ functional group, and the
nucleophile is an _______________________ anion; these two reactants react to form a ____________________________________________
functionality in the product. Give an example of an aldol addition reaction from the class notes in the box below. (6 pts)
O
O
O
2
NaOEt and
5
O
OH
OOH
6
Compound 5 facts:
* an aldol addition product
* MF is C17H22O4
* has 3 different types of oxygen-
containing functional groups
STEP B
4
STEP C Reagents?
+ HO
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
6
Q2(b). Compound 2 reacts with NaOEt to form a(n) _____________________________. (2 pts)
What atom in compound 2 reacts with NaOEt? Draw in and circle this atom in this structure
(compound 2). (2 pts)
Q2(c). Looking ahead and working backwards (yes, a dizzy scavenger hunt!), compare compound 2 to compound 6. Circle the
new or different structural features in compound 6 that make it different from compound 2. (3 pts)
Q2(d). What part/piece of compound 6 was accomplished by aldol addition reaction? Describe in words. (3 pts)
Q2(e). Using your answers from parts (a-d), draw the skeletal structure of
compound 4 (the needed reactant for this aldol addition reaction) in this empty
ox. (4 pts)
O
O
O
2
O
O
O
2
O
OH
OOH
6
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
7
Q2(f). Making connections! Using a short bullet list, list three (3) similarities between STEP A and STEP B: (3 pts)
• Both reactions ______________________________________________________________________________________________________.
• Both reactions ______________________________________________________________________________________________________.
• Both reactions ______________________________________________________________________________________________________.
Q2(g). Draw the complete mechanism of STEP B. Include all electron-pushing a
ows and structures of all intermediates with
formal charges where appropriate. (6 pts)
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
8
GOAL for Question 3: Determine the required reagents for STEP C.
Q3(a). Refe
ing to your answer for Q2(c), STEP C (on page 5) is the reaction of the __________________________ functional group in
compound 2 that is being transformed into the _______________________________________ functional group in compound 6. (2 pts)
Q3(b). Given your answers in Q3(a), the required reagents for STEP C are ________________________________________________________.
(3 pts)
YOU’VE COMPLETED THE FIRST TRANSFORMATION!!
NOW, onto the second transformation of this Synthetic Scavenger Hunt!
The second transformation will take compound 5 into a different direction! Here’s an overview of the second transformation:
2 CH3CH2MgB
then H3O+
work-up
8
+ HOCompound 5
OH
O
OOH
7
STEP E
STEP D
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
9
Question 4: STEP D!
GOALS for Question 4:
• Identify how compound 5 is transformed to
compound 7
• Determine the required reagents for STEP D.
Q4(a). Redraw your determined structure of compound 5 below in the empty box and answer the question:
5
Circle what is changing in compound 5 (drawn above in the box) and circle what is “new” in compound 7. (3 pts)
Q4(b). What reagents will achieve the reaction from compound 5 to compound 7 (STEP D)? (3 pts)
Q4(c). Describe this transformation using words – be as technical as possible! (4 pts)
Compound 5
OH
O
OOH
7
STEP D
OH
O
OOH
7
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
10
Q4(d). Quick side diversion! Explain why a ketone is more reactive as an electrophile than an ester. Please reference and use
your class notes to answer this question. (4 pts)
Question 5: STEP E!
GOALS for Question 5:
• Identify the reactive sites
in the reactant and given
eagent.
• Determine the structure of
compound 8, which is the
product of STEP E.
Q5(a). Give the two different types of functional groups in compound 7: ________________________ and ________________________. (2 pts)
Q5(b). The reagent CH3CH2MgBr is a __________________________ (name) reagent. The reactive site is ________________________________ (be
as specific as possible!). (3 pts)
Q5(c). Given your answer in part (b), the function of compound 7 is a ( electrophile / nucleophile ), and the reactive site is
the _______________ atom of the ____________________ bond of the __________________ functional group. (4 pts)
Q5(d). In STEP E, ethanol is one of two products. From where does the OR group of this alcohol come? Explain. (3 pts)
2 CH3CH2MgB
then H3O+
work-up
8
+ HO
OH
O
OOH
7
STEP E
CHEM 202 CS 2: Polar Basic Reactions Dr. Masters
11
Q5(e). Draw the complete mechanism of STEP E. You must include electron-pushing a
ows, all intermediates with formal
charges where appropriate. You must also use the 2 reagents given with the reaction (2 CH3CH2MgBr) and use the hydronium
work-up. Please circle the product (compound 8) in your mechanism. (8 pts)