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CHEM104: Organic Chemistry II

Unit 4: Benzene and the Other Aromatic Compounds   Benzene is considered the "parent" molecule of all aromatic compounds.  Aromatic compounds are characterized by a network of delocalized electrons in Pi orbitals.  The aromatic system confers an enhanced thermodynamic stability to the molecule (i.e. it is more stable than if the same molecule had isolated Pi bonds).  Aromatic systems react very differently from the other functional groups you have encountered so far in this course.  The most typical reaction is electrophilic substitution, where one substituent at the aromatic ring (this can be an H, a halogen, etc) is substituted with another group (an acyl group or a nitro group, for instance). Simple aromatics are usually obtained from the distillation of crude oil and then used as building blocks for the synthesis of larger molecular structures.  Aromatics have numerous applications, including plasticizers and solvents.  In this unit, you will learn how to plan the modification of aromatic systems with the goal of synthesizing more valuable products.

Unit 4 Time Advisory
This unit will take you 26.5 hours to complete.

☐    Subunit 4.1: 8.75 hours ☐    Reading: 2 hours

☐    Lecture: 0.75 hour

☐    Web Media: 6 hours

☐    Subunit 4.2: 5.25 hours ☐    Reading: 3 hours

☐    Web Media: 2.25 hours

☐    Subunit 4.3: 10.25 hours

☐    Sub-subunit 4.3.1: 5.75 hours

☐    Reading: 3 hours

☐    Lecture: 0.5 hour

☐    Web Media: 2.25 hours

☐    Sub-subunit 4.3.2: 2.5 hours

☐    Sub-subunit 4.3.3: 2 hours

☐    Subunit 4.4: 2.25 hours

Unit4 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- Derive the name of aromatic compounds and substituted benzene rings from their molecular structure, and vice versa. - Describe aromatic systems using molecular orbital theory and determine whether a molecule is aromatic, anti-aromatic, or non-aromatic. - Identify the properties of phenols verses aliphatic alcohols. - Describe the mechanism of aromatic electrophilic substitution, aromatic nucleophilic substitution, addition, hydrogenation, and oxidation reactions. - Plan the synthesis of substituted aromatic systems from simple reagents.

4.1 Nomenclature, Structural, and Physical Properties   - Reading: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Aromaticity” Link: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Aromaticity” (HTML)

 Instructions: Read the section titled “Aromaticity.” Complete the
practice problems at the end of the section in order to test
yourself on the identification of aromatic systems.  

 Reading, taking notes, and completing the practice problems should
take approximately 2 hours.  
    
 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-NonCommercial-NoDerivs 3.0
License](http://creativecommons.org/licenses/by-nc-nd/3.0/). It is
attributed to Professor William Reusch, and the original version can
be found
[here](http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/react3.htm#rx8).

4.2 Phenols (Aromatic Alcohols)   - Reading: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Phenols" Link: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Phenols" (HTML)

 Instructions: Read the section titled “Phenols." Scroll down to the
problem set labeled “Reactions of Alcohols and Phenols” from the
drop down menu, and follow the instructions on the webpage to
complete the problem set. The problems on alcohols will give you a
refresher and allow you to compare those with those of phenols.  

 Phenols are organic compounds having a hydroxyl group bonded to an
aromatic ring. Chemically, phenols behave differently from alcohols.
One important difference between the chemistry of phenols and
alcohol compounds is that for the most part, phenols do not
eliminate or undergo substitution of the hydroxyl group in chemical
reactions; recall that alcohols do. This section will aid your
understanding of this difference in reactivity.    

 Reading, taking notes, and completing the practice problems should
take approximately 3 hours.  

 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-NonCommercial-NoDerivs 3.0
License](http://creativecommons.org/licenses/by-nc-nd/3.0/). It is
attributed to Professor William Reusch, and the original version can
be found
[here](http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/alcohol2.htm#alcrx5).

4.3 Reactivity   4.3.1 Electrophilic Substitution   - Reading: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Aromatic Substitution Reactions: Substitution Reactions of Benzene and Other Aromatic Compounds” Link: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Aromatic Substitution Reactions: Substitution Reactions of Benzene and Other Aromatic Compounds” (HTML)
 
Instructions: Read this webpage, then click on the link to “Part II” at the bottom of the webpage, and continue reading the rest of the chapter. Unlike alkenes, substitution reactions in benzene occur in preference to addition reaction. In this section, you will learn about the five most useful substitution reactions when benzene reacts with electrophiles in ‘electrophilic aromatic substitution’ reactions.

 Reading and taking notes should take approximately 3 hours to
complete.  

 Terms of Use: This resource is licensed under a [Creative Commons
Attribution-NonCommercial-NoDerivs 3.0
License](http://creativecommons.org/licenses/by-nc-nd/3.0/). It is
attributed to Professor William Reusch, and the original version can
be found
[here](http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/benzrx1.htm#benz1)
and
[here](http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/benzrx2.htm#benz8).

4.3.2 Nucleophilic Substitution, Elimination, and Addition Reactions   - Reading: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Nucleophilic Substitution, Elimination, and Addition Reactions of Benzene Derivatives” Link: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: “Nucleophilic Substitution, Elimination, and Addition Reactions of Benzene Derivatives” (HTML)

 Instructions: Please click on the link above, and read the entire
chapter titled “Nucleophilic Substitution, Elimination, and Addition
Reactions of Benzene Derivatives.”  Notethat nucleophilic aromatic
substitution is a type of reaction wherein the aromatic ring is an
electrophile that reacts with nucleophiles.  You should understand
under which conditions an aromatic system becomes an electrophile.  
    
 Reading and taking notes should take approximately 1 hour to
complete.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above. 
  • Web Media: YouTube: Freelanceteach’s "Nucleophilic Aromatic Substitution (1)" Link: YouTube: Freelanceteach’s "Nucleophilic Aromatic Substitution (1)" (YouTube)

    Instructions: Please click on the link above, and watch this video (#1) in its entirety (10:15 minutes) to continue learning about the nucleophilic aromatic substitution.  This resource covers subunits 4.3.2.
     
    Viewing this lecture and pausing to take notes should take approximately 15 minutes to complete.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.  

  • Web Media: YouTube: Freelanceteach’s “Nucleophilic Aromatic Substitution (2);” “Nucleophilic Aromatic Substitution (3);” “Nucleophilic Aromatic Substitution (4);” “Nucleophilic Aromatic Substitution (5);” “Nucleophilic Aromatic Substitution (6);” “Nucleophilic Aromatic Substitution (7);” and “Nucleophilic Aromatic Substitution (8)” Links: YouTube: Freelanceteach’s “Nucleophilic Aromatic Substitution (2);” Nucleophilic Aromatic Substitution (3);” “Nucleophilic Aromatic Substitution (4);” “Nucleophilic Aromatic Substitution (5);” “Nucleophilic Aromatic Substitution (6);” “Nucleophilic Aromatic Substitution (7);” and “Nucleophilic Aromatic Substitution (8)”  (YouTube)
     
    Instructions: Please note that these video lectures are optional.  For an in-depth explanation on the mechanisms of nucleophilic aromatic substitution, you may choose to click on the links above and watch the video lectures for “Nucleophilic Aromatic Substitution 2-8.”  These videos vary in run time from 7 minutes to 11 minutes.  This material is not required for successful completion of the course.
     
    Viewing these optional lectures should take approximately 1 hour and 15 minutes to complete.
     
    Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.

4.3.3 Practice Problem Solving with Aromatic Chemistry   - Assessment: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: "Practice Problems" Link: Michigan State University: Professor William Reusch’s Virtual Textbook of Organic Chemistry: "Practice Problems" (HTML)

 Instructions: Please complete this assessment after working through
subunit 4.3.2.  At the bottom of the webpage, choose a practice
problem from the scroll down menu and practice on the topic you
want/need.  These practice problems will reinforce what you have
learned in this unit about amine nomenclature, synthesis, and
reactions.  There is also a multi-step synthesis for you to work
through.  This resource covers subunits 4.1-4.3 and all their
inclusive sub-subunits.  

 You should dedicate approximately 2 hours to practicing with these
problem sets.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.

4.4 Synthetic Strategies for Substituted Benzenes   - Web Media: YouTube: Freelanceteach’s "Synthetic Strategies for Substituted Benzenes (1)" Link: YouTube: Freelanceteach’s "Synthetic Strategies for Substituted Benzenes (1)" (YouTube)

 Instructions: Please click on the link above, and watch this video
(\#1) in its entirety (10:33 minutes) to learn how to synthesize
substituted benzenes using multiple reactions.  Complex molecular
structures containing aromatic rings are often produced using
"multistep synthesis". In multistep syntheses, the final product is
assembled throughout a sequence of chemical reactions.  In this
section, you will learn how to utilize different types of reactions
to produce the desired molecule.This resource covers subunits
4.1-4.3 and all their inclusive sub-subunits.  
    
 Viewing this lecture and pausing to take notes should take
approximately 15 minutes to complete.  
    
 Terms of Use: Please respect the copyright and terms of use
displayed on the webpage above.