~~there are extra practice problems at the end of ws-4 and

CHEM 244 - Organic Chemistry II – Spring 2021

Worksheet #4: Videos 16-1 to 16-4

Worksheet #5: Videos 17-1 to 17-4

(NOTE: This document contains both Worksheets #4 & #5)

Target date for completion of Worksheet #4: March 31

Target date for completion of Worksheet #5: April 9

Complete the following worksheet by the target date by (1) working with a group of students during class time, and (2)

working on your own outside of class. You can use the CHEM 244 course web page, and any resource available to you,

but I strongly discourage the use of Wikipedia and online homework sites (like Chegg). During class time you will get

help from the course instructor, the Peer Leaders, and other students.

The purpose of this worksheet is to apply the principles you learned in the corresponding lecture videos. I will NOT

collect this worksheet. I advise you to print this worksheet and answer the questions in the space provided. I encourage

you to save this worksheet in your course notebook for study purposes, and I will post an answer key.

~~There are extra practice problems at the end of WS-4 and WS-5~~

Dates CHEM 244 Videos Classwork Class

Project

March 24 16-1 & 16-2 WS-4, problems 1-5 Yes

March 26 16-2 & 16-3 WS-4, problems 4-8 Yes

March 29 16-4 WS-4, problems 9-12 Yes

March 31 Catch-up WS-4 catch-up (1-12) Yes

April 2 Group Quiz #4 N/A

April 5 17-1 & 17-2 WS-5, problems 20-25 Yes

April 7 17-3 & 17-4 WS-5, problems 26-33 Yes

April 9 Catch-up WS-5 catch-up (20-33) Yes

April 12 Group Quiz #5 N/A

April 14 Exam #3 (WS 4 & 5) N/A

Our Goals for the remaining weeks:

I. Work more Efficiently! Be focused and try completing worksheets at a faster pace.

II. Watch the Videos! Lets all make a better effort to come to class prepared and ready to contribute to your group.

III. Practice! You are individually responsible for completing any unfinished worksheet problems outside of class, and

for doing the extra practice problems.

IV. Lets be Seen and Heard! In all breakout rooms, lets all try to turn ON our cameras and microphones. Lets try to

contribute to the problem solving, OR ask questions.

V. Respect! Lets all be respectful of each other! There are always reasons why any one of us (including Dr. EJB) may not

be prepared for a specific class. There are also reasons why a student may not be comfortable turning on their camera or

mic, or contributing to a discussion. But we can all still talk with each other!

VI. Take Control! The Peer Leaders and I will guide you on the worksheets, BUT you all need to take more

responsibility in the “problem solving”. Use your notes and discuss questions with your group before asking for help.

http://webhost.bridgew.edu/ebrush/CH343%20audio.htm

http://webhost.bridgew.edu/ebrush/CH344%20audio.htm

~~~ Worksheet #4 ~~~

WS-4, Video 16-1

(1) Aldehyde and Ketone Nomenclature. If a name is given, draw the correct chemical structure. If a structure is given,

give the IUPAC name. Be sure to include the R/S configurations for any chiral carbons.

(a) (3S, 4R)-4-chloro-3-cyclopropyl hexanal

(c) 3-chloro-5-phenyl acetophenone

(2) Review of Carbonyl Reactions from earlier chapters. Complete the following reactions involving aldehydes and

ketones by drawing the structure of the neutral organic products.

(3) Structure Identification. An unknown organic compound (C7H14O) was analyzed by IR and NMR.

(a) The IR spectrum is shown below. What does the IR suggest about the structure of the unknown? You must write the

relevant wave numbers and name the functional group(s).

(b) The 1H NMR data for the unknown are given in the table below. Using this information draw structural fragments for

each signal in the boxes under the table. H nuclei (a) (b) (c) (d) (e)

Chemical shift 1.9 ppm 2.8 ppm 3.2 ppm 1.4 ppm 1.1 ppm

# of protons 3H 2H 2H 1H 6H

Splitting t q d m d

(a) (b) (c) (d) (e)

(c) Based on the data above, suggest one possible structure for this unknown. ***Don’t forget the IR info!!!

(d) Complete the table below for what you expect in the 13C NMR for the unknown structure you drew in (d).

Total aromatic 13C signals

Total 13C signals

Total H-coupled signals that would appear as singlets

Total H-coupled signals that would appear as doublets

Total H-coupled signals that would appear as triplets

Total H-coupled signals that would appear as quartets

WS-4, Video 16-2

(4) Carbonyl Reactivity. Consider the charge distribution of the carbonyl dipole (+ and -) and rank the following

compounds in order of carbonyl group reactivity toward nucleophilic addition: 1 = most reactive and 5 = least reactive.

_______ _______ _______ _______ _______

(5) Mechanisms: Acid catalyzed addition of H2O to an aldehyde (3 steps). The PARTIAL mechanism (series of

balanced chemical equations) has been done for you. All you need to do is add the curved arrows and proper charges.

STEP #1

STEP #2

STEP #3

WS-4, Video 16-3

(6) Reactions of the Carbonyl Group of Aldehydes and Ketones. Complete the following reactions involving

aldehydes and ketones by drawing the structure of the neutral organic products. For the reactions marked by an

asterisk (*) you should also practice the mechanism.

(7) Mechanisms: Intramolecular acid-catalyzed addition of an alcohol to a ketone (6 steps). The PARTIAL

mechanism (series of balanced chemical equations) has been done for you. All you need to do is add the curved arrows

and proper charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

STEP #6


(a) The IR spectrum has a strong, sharp band at 1700 cm-1, and a series of very weak bands between 1800-2000 cm-1.

Write the name of the functional group(s) suggested.


each signal in the boxes under the table. H nuclei (a) (b) (c) (d)

Chemical shift 7.2 ppm 2.5 ppm 2.8 ppm 9.8 ppm (what type of “H” does this chemical shift suggest?)

# of protons 5H 6H 2H 1H

Splitting ------- s d t

(a) (b) (c) (d)

(c) Based on the data above, suggest

one possible structure for this unknown:



Total 13C signals

Total 13C signals that would appear as singlets

Total 13C signals that would appear as doublets

Total 13C signals that would appear as triplets

Total 13C signals that would appear as quartets

WS-4, Video 16-4


aldehydes and ketones by drawing the structure of the neutral organic products. For the reactions marked by an

asterisk (*) you should practice the mechanism.

(10) Mechanism: Addition of cyanide to a ketone to form a cyanohydrin (2 steps). The PARTIAL mechanism (series

of balanced chemical equations) has been done for you. All you need to do is add the curved arrows and proper charges.

STEP #1

STEP #2

(11) Mechanisms: Dilute-Acid Catalyzed Addition of an Amine to a Ketone (5 steps). The PARTIAL mechanism

(series of balanced chemical equations) has been done for you. All you need to do is add the curved arrows and proper

charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(12) Structure Identification. An unknown organic compound has a formula of C11H16O, & was analyzed by IR & NMR.

(a) The IR spectrum is shown below. What does the IR suggest about the structure of the unknown? You must write the:

(i) relevant wave numbers and (ii) name the indicated functional group(s).


each signal in the boxes under the table. H nuclei (a) (b) (c) (d) (e) (f) (g) **

Chemical shift 7.3 ppm 3.8 ppm 2.7 ppm 3.4 ppm 3.0 ppm 1.3 ppm 3.7 ppm**

# of protons 4H 2H 2H 1H 3H 3H 1H**

Splitting ------- q d m d t s

**Signal disappears when D2O was added to the NMR sample.

(a) (b) (c) (d)

(e) (f) (g)

(c) Based on the data above, suggest one

possible structure for this unknown:

(d) Complete the table below for what you might expect in the 13C NMR for the unknown structure you drew in part (d).


Total 13C signals





~~~ Extra practice problems for Worksheet #4 ~~~

(13) Aldehyde and Ketone Nomenclature. If a name is given, draw the correct chemical structure. If a structure is

given, give the IUPAC name. Be sure to include the R/S configurations for any chiral carbons.

(a) (4S, 5S)-5-chloro-4-methyl-1-phenyl-3-hexanone

(c) 2-isopropyl-4-fluoro cyclopentanone

(14) Carbonyl Reactivity. Rank the following ketones in order of carbonyl group reactivity toward nucleophilic

addition.

(1 = most reactive and 4 = least reactive).

_______ _______ _______ _______


aldehydes and ketones by drawing the structure of the neutral organic products. You should also practice the

mechanism for these reactions.

(16) Mechanism: Acid Catalyzed Addition of Alcohols to a Ketone (6 steps). The PARTIAL mechanism (series of


STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

STEP #6

(17) Mechanism: Addition of cyanide to an aldehyde to form a cyanohydrin (2 steps). The PARTIAL mechanism


charges.

STEP #1

STEP #2

(18) Mechanisms: Dilute-Acid Catalyzed Addition of an Amine to a Ketone (5 steps). The PARTIAL mechanism


charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5


(a) The IR spectrum is shown at the right. What

does the IR suggest about the structure of the

unknown? You must write the relevant wave

numbers and name the functional group(s).


each signal in the boxes under the table. H nuclei (a) (b) (c) (d) (e) (f)

Chemical shift 7.2 ppm 2.9 ppm 1.7 ppm 2.1 ppm 3.2 ppm 2.5 ppm

# of protons 4H 2H 3H 3H 1H 3H

Splitting ------- q t d q s

(a) (b) (c) (d) (e) (f)

(c) Based on the data above, suggest

one possible structure for this unknown.



Total 13C signals





~~~ Worksheet #5 ~~~

WS-5, Video 17-1

(20) Carboxylic Acid Nomenclature. If a name is given, draw the correct chemical structure. If a structure is given,


(a) (2S, 4R)-4-bromo-2-cyclopropyl-hexanoic acid

(c) 3-butyl-4-phenyl benzoic acid

(21) Acids Strength. Rank these

carboxylic acids in order of acidity

(1 = strongest…4 = weakest).

_______ _______ _______ _______

(22) Structure Identification. An unknown compound with formula C7H14O2 was analyzed by IR and NMR.

(a) IR Spectrum. What are the significant absorption bands, and what functional group(s) are suggested?

(b) Compound A was found to be insoluble in water, but soluble in dilute aqueous base. EXPLAIN what this solubility

information tells you about the unknown.

(c) The 1H NMR data for Compound A are given in the table below. Using this information draw structural fragments for

each signal in the boxes under the table. **Signal disappears when D2O was added to the NMR sample.

H nuclei (a) (b) (c) (d) (e) (f)

Chemical shift 12.3 ppm** 3.9 ppm 3.1 ppm 2.2 ppm 2.7 ppm 1.3 ppm


Splitting s d m d m d

(a) (b) (c)

(d) (e) (f)

(d) Based on the data above, suggest one


(e) Complete the table below for what you expect in the 13C NMR for the unknown structure you drew in (d).


Total 13C signals





WS-5, Video 17-2

(23) Carboxylate ion Base Strength. Rank the following carboxylate ions in order of their basicity (1 = most basic and 4

= least basic). HINT: If EWGs lead to a stronger acid, then………

_______ _______ _______ _______

(24) Reactions. Complete the following Nucleophilic

Acyl Substitution (NAS) reactions by drawing the

structure of the organic products only. Remember,

all NAS reactions follow this general format:

acid chloride reaction (this will be the only time you will see this reaction):

ester synthesis:

ester hydrolysis:

(25) Mechanisms: Acid-catalyzed addition of an alcohol to a carboxylic acid (5 steps). The PARTIAL mechanism


charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

WS-5, Video 17-3

(26) Reactions. Complete the following Nucleophilic Acyl Substitution

(NAS) reactions by drawing the structure of the organic products

only. Remember, all NAS reactions follow this general format:

ester synthesis:

ester hydrolysis:

ester exchange:

(27) Mechanisms: Acid-catalyzed hydrolysis of a (cyclic) ester (5 steps). The PARTIAL mechanism (series of


STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(28) Mechanisms - Acid-Catalyzed Ester Exchange of a Cyclic Ester (5 steps). The PARTIAL mechanism (series of


STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(29) Structure Identification. An unknown compound contains only C, H & O, and is believed to be either an alcohol,

aldehyde, ketone, carboxylic acid, or ester. Analysis included chemical tests, IR/NMR.

(a) The following chemical tests were performed on the unknown:

(i) It was insoluble in dilute aqueous base.

(ii) The unknown reacted with NH3 (H3O+ catalyst), and one organic product was formed.

(iii) The unknown reacted with NaBH4 to form one product.

Based on these chemical tests, place an “X” on all possibilities that have been eliminated:

alcohol aldehyde ketone carboxylic acid ester

(b) The IR spectrum for the unknown has a strong, sharp band at 1700 cm-1, and a series of minor bands between 1800-

2000 cm-1. Identify the key functional groups by wave number and name.

(c) The 1H NMR data for the unknown are given in the table below:

H nuclei (a) (b) (c) (d) (e) (f)

Chemical

shift 1.1 ppm 2.2 ppm 2.8 ppm 3.5 ppm 3.1 ppm

7.2

ppm


Splitting d m d s s --------

Using the NMR information, draw structural fragments for each signal in the boxes below.

(a) (b) (c)

(d) (e) (f)

(d) Based on the data above, draw one


(e) Complete the table below for what you expect in the 13C NMR for the unknown structure you drew above.


Total 13C signals





WS-5, Video 17-4

(30) Reactions. Complete the following Nucleophilic Acyl Substitution (NAS) reactions by drawing the structure of the

organic products only.

(31) Mechanisms: Un-catalyzed synthesis of an amide from an ester (3 steps). The PARTIAL mechanism (series of


STEP #1

STEP #2

STEP #3

(32) Mechanism: Acid-Catalyzed Amide Hydrolysis (5 steps). The PARTIAL mechanism (series of balanced

chemical equations) has been done for you. All you need to do is add the curved arrows and proper charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(33) Structure Identification. An unknown compound contains only C, H & O, and is believed to be either an alcohol,

aldehyde, ketone, carboxylic acid, or ester. Analysis included simple chemical tests, IR and NMR.

(a) The IR spectrum for the unknown has a strong, sharp band at 1700 cm-1, a series of minor bands between 1800-2000

cm-1, and a broad band between 2500-3300 cm-1. Identify the key functional groups by wave number and name:

(b) Do you expect that the unknown will be soluble in dilute aqueous base? Explain your answer.

(c) The 1H NMR data for the unknown are given in the table below:

H nuclei (a) (b) (c) (d) (e) (f)***

Chemical

shift 1.1 ppm 2.2 ppm 2.8 ppm 3.5 ppm 7.1 ppm 12.2

ppm


Splitting d m d m ------ s

***This signal disappears when D2O is added to the NMR sample.

Using the NMR information, draw structural fragments for each signal in the boxes below.

(a) (b) (c)

(d) (e) (f)

(d) Based on the data above, draw one

possible structure for this unknown.

(e) Complete the table below for what you expect in the 13C NMR for the unknown structure you drew above.


Total 13C signals





~~~ Extra practice problems for Worksheet #5 ~~~

(34) Carboxylic Acid Nomenclature. If a name is given, draw the correct chemical structure. If a structure is given,


(a) (2R, 4S)-2-cyclopentyl-4-phenyl heptanoic acid

(35) Base Strength. Rank the following carboxylate ions in order of base strength (1 = strongest…4 = weakest)

_______ _______ _______ _______

(36) Acid Strength. Rank these carboxylic acids in order of acid strength: (1 = strongest…..4 = weakest).

_______ _______ _______ _______

(37) Reactions. Complete the reactions shown below by drawing the structure of the organic products only.

(38) Mechanisms - Acid-catalyzed addition of an alcohol to a carboxylic acid (5 steps). The PARTIAL mechanism


charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(39) Mechanism: Un-Catalyzed synthesis of an amide from an ester (3 steps). The PARTIAL mechanism (series of


STEP #1

STEP #2

STEP #3

(40) Mechanism: Acid-Catalyzed Ester Hydrolysis (5 steps). The PARTIAL mechanism (series of balanced chemical

equations) has been done for you. All you need to do is add the curved arrows and proper charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(41) Mechanism: Acid-Catalyzed Hydrolysis of an Amide (5 steps). The PARTIAL mechanism (series of balanced

chemical equations) has been done for you. All you need to do is add the curved arrows and proper charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(42) Acid-Catalyzed Ester Exchange (5 steps). The PARTIAL mechanism (series of balanced chemical equations) has

been done for you. All you need to do is add the curved arrows and proper charges.

STEP #1

STEP #2

STEP #3

STEP #4

STEP #5

(43) Mechanisms - Un-catalyzed synthesis of an amide from an ester (3 steps). The PARTIAL mechanism (series of


STEP #1

STEP #2

STEP #3

(44) Structure Identification. Unknown Compound A contains only C,H,O, and is believed to be either an alcohol,

aldehyde, ketone, carboxylic acid, or ester.

(a) The IR spectrum for Compound A has a strong, sharp band at 1700 cm-1, and a series of weak jaggered bands between

1800-2000 cm-1. Is this data consistent with an alcohol, aldehyde, ketone, carboxylic acid, or ester? Explain. Do the

data suggest any other functional groups?

(b) Reaction of Compound A with H2O (catalyzed by H2SO4) produces two new compounds, B and C. The IR spectrum

for Compound B has a broad band at 2800-3300 cm-1, weak jaggered bands between 1800-2000 cm-1, and a sharp band at

ca. 1700 cm-1. Compound B is insoluble in water, but soluble in dilute aqueous base. Compound C has a broad IR band at

3200-3600 cm-1. What does all this information suggest about Compounds A, B, and C?

(c) The 1H NMR data for Compounds B and C are summarized in the Tables below. Draw a possible structural fragment

for each signal.

COMPOUND B (*After adding D2O, these signals disappear) COMPOUND C H nuclei (a) (b) (c) (d) (e) (f) (g) (h)

Chemical shift 2.9 ppm 2.4 ppm 7.2 ppm 12.4 ppm* 0.9 ppm 1.8 ppm 2.9 ppm 3.3 ppm*

# of protons 2H 2H 5H 1H 6H 1H 2H 1H

Splitting t t ------- s d m d s

(a) (b) (c) (d)

(e) (f) (g) (h)

(d) Based on the NMR data, propose structures for compounds B, C, and finally, A.

(e) The 13C NMR sample tubes for A, B, and C were mixed up. After running the 13C NMR for each tube (I, II, III), the

following data were obtained. Assign the appropriate compound (A, B, C) to Tube I, II or III.

TUBE I _______ TUBE II _______ TUBE III _______

190 ppm (s) 190 ppm (s) 32 ppm (t)

141 ppm (s) 141 ppm (s) 23 ppm (d)

130 ppm (d) 130 ppm (d) 18 ppm (q)

124 ppm (d) 124 ppm (d)

117 ppm (d) 117 ppm (d)

35 ppm (t) 35 ppm (t)

32 ppm (t) 28 ppm (t)

28 ppm (t)

23 ppm (d)

18 ppm (q)

~~there are extra practice problems at the end of ws-4 and

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