Handouts, Spring 2011

Lecture-related material

• Course syllabus (PDF)
• Laboratory manual (1MB PDF)
• Organic acids and bases
• 1/12/2011: Organic qualitative analysis, points of unsaturation and getting from a molecular mass to a formula. Mass spectrometry.
  • Powerpoint
• 1/14, 1/19/2011: Infrared spectroscopy and Fourier transforms.
  • Powerpoint
  • IR Examples. Look these over and bring any questions to class on 1/19.
• 1/21/2011: Introduction to NMR spectroscopy
  • Powerpoint
• 1/24, 1/26/2011: Splitting patterns and integration in NMR; COSY
  • powerpoint
• 1/28/2011: C-13 NMR including DEPT
  • C-13 NMR
  • C-13 practice problems and answers
• 1/31 through 2/2/2011:Interpreting combined H-1 and C-13 data
  • combined spectroscopy practice problems and answers
• 2/7 through 2/9/2011: Molecular orbital theory and Valence bond theory
  • Powerpoint
    • printable version
  • Chapter 1 textbook notes
• 2/11/2011: pi-molecular orbitals and the stability of benzene
  • conjugation as seen by MO theory
    • Resonance energies of six-carbon compounds
  • bonding in benzene
  • how to construct π MOs for linear poly-enes
  • Hyperconjugation and the stability of cyclohexadiene
  • Section 7.8 and Chapter 14 textbook notes
• 2/14/2011: UV/VIS spectroscopy and conjugation
  • powerpoint
  • Chapter 12 (UV/VIS) textbook notes (last page)
• 2/16 through 2/18/2011: Conformation and strain
  • Chapter 2 notes, sections 2.10-2.14
  • Conformation and Newman Projections on the Molecular Models website
  • WebMO assignments:
    • Conformational analysis of butane and 2-methylhexane
    • Strain in saturated ring systems
• 2/24/2011: Thermodynamics and kinetics
  • Reaction rates and equilibria
  • Outline of topics on reaction energy diagrams
  • Answers to today's quiz
• 2/26/2011: The Diels-Alder reaction
  • The important points covered in the chapter and lecture
  • Online molecular models and orbital diagrams illustrating the basic concepts
    • The transition state geometry for the basic Diels-Alder reaction
    • The geometry for endo and exo addition
• 2/25/2011: Nucleophilic substitution reactions in more depth
  • Notes for Chapter 8
  • Nucleophilic substitution
  • MO explanations of reactivity (covers some of the same material)
  • Reaction animations
    • S_N2
    • S_N1
  • Quiz on Diels-Alder reactions (answers will be posted on Monday)
• 2/28/2011: Elimination reactions in more depth
  • Notes for Chapter 9
  • MO explanations of reactivity
  • Reaction animations
    • E2
    • E1
  • Today's chat transcript (edited for clarity)
• 3/2/2011: Review
• 3/14/2011: Organometallic couplings and a review of Carbonyl I reactions
  • Powerpoint with notes, reiterates Section 10.13
• 3/16/2011: Mechanisms of free-radical chain reactions
  • Powerpoint
  • Chapter 11 notes
  • Quiz (with answer key), taken from the problem assignment for 3/14.
• 3/18/2011: Synthetic utility of free-radical chain reactions
  • Chapter 11 notes
• Aromaticity and the rules for aromatic compounds; MO pictures of aromatic compounds.
  • Bonding in benzene and other aromatic compounds
• 3/21/2011:. Electrophilic aromatic substitution, and the effects of existing substituents on the ring.
  • Outline notes for Sections 15.1-15.8
  • Take-home quiz, due on Monday, 3/21/2011; answer key is now included
• 3/23/2011: Electrophilic aromatic substitution, and considerations in how to design syntheses of polysubstituted aromatic compounds.
  • Outline notes for Sections 15.1-15.7
• 3/25 and 3/28/2011: Arenediazonium salts and their use in synthesis; nucleophilic aromatic substitution; benzyne reactions
  • Outline notes for Sections 15.9-15.13 (15.14 is purely informational)
  • Quiz given on 3/28 (answers included)
• 3/30/2011: Review of Chapter 16, Chapter 17.1-10
  • Reaction review from Chapter 16
  • Notes on Sections 17.1-17.10
• 4/1/2011: Synthons and disconnects; protecting groups and the Wittig reaction
  • Chapter 17 notes for sections 17.11 on. Use these to guide your reading of the chapter.
• 4/4/2011: Introduction to α,β-unsaturated carbonyls; keto-enol tautomerism review
  • Chapter 17 notes for sections 17.11 on. Use these to guide your reading of the chapter.
  • Chapter 18 notes (we will be looking at 18.1-18.3 only today). Use these to guide your reading of the chapter.
• 4/11/2011: Re-review of Chapter 16 and 17 reactions
  • Today's quiz, with answer key included
• 4/13/2011: Review of Chapter 17.
  • Today's quiz, with answers included.
• 4/15/2011: Continue review of Chapter 17. In-class work is review of selected text problems. α,β-unsaturated carbonyl compounds; acidity of C-H bonds α to carbonyls and other EWGs (see the reading).
  • Take-home problems are due 4/18 at class time; you are permitted to work together on these problems.
  • It is strongly recommended that you work out your own answers, rather than everyone copying uncritically from one set as has happened in the past.
    You are expected to double-check your reactions. No credit will be given for reactions that do not do what you claim they do.
• 4/18/2011: Enols, enolates and enamines: substitution α to carbonyl groups; the Aldol reaction and E1_CB reactions (see your textbook)
  • Chapter 18 notes. Use these to guide your reading of the chapter.
  • 4/20/2011: Enolate nucleophiles, carbonyl electrophiles: The Michael, Stork, Aldol and Claisen reactions. Check the textbook for mechanisms.
    • Synthetic utility of these reactions (new bonds shown in red)
    • Chapter 18 notes. Use these to guide your reading of the chapter.
    • Take-home problems were due on 4/27 Answers are now included.
  • 4/27/2011: Cyclization and decarboxylation reactions: the Dieckmann cyclization; intramolecular Aldol; the Robinson annulation; the Malonic and Acetoacetic Ester syntheses
    choosing methods for synthesis
    • Chapter 18 notes. Use these to guide your reading of the chapter.
    • Today's quiz, with answers.

  Homework problems

  • Due 1/19/2011: a synthesis problem that can be solved using reactions from last semester. Answers
  • Quiz, 1/19/2011: Identifying functional groups from IR spectra. Quiz, answers
  • Due 1/24/2011: mechanism problems; answers
  • Due 1/31/2011: synthesis and structural analysis problems; answers
  • Take-home problems are due 4/18 at class time; you are permitted to work together on these problems.

  Exam answers

  • CEM 221 exams, Fall 2010
  • Exam 1, and the answers
  • Exam 2 and the answers
  • Exam 3 and the answers
  • No answers will be posted for the final exam, which is the ACS Organic Chemistry exam.

  WebMO exercises

  WebMO login

  Learn to use WebMO

  This is the color version; the black-and-white version was handed out in class on January 10. Familiarize yourself with some of the features of WebMO. No credit.

  Predicting IR spectra

  In this exercise, you will use WebMO to predict infrared spectra. You will examine structural effects on bond vibrations, and the reliability of different computational methods for predicting vibrational frequencies. This exercise is due by 4 PM on Friday, January 28.

  Keto-enol stability

  We will use WebMO to examine the stabilities of the enols of four β-dicarbonyl compounds. The results of this study are to be integrated into your report on the experiment examining keto/enol equilibria by NMR.

  Molecular orbitals of polyenes

  WebMO or ArgusLab can be used to examine the π-molecular orbitals of alkenes ethene through hexatriene, along with the 3- and 5-carbon analogs. Compare your MOs to those generated using a simple, qualitative method. This assignment is due February 25.

  Dihedral angles and rotational isomers

  Rotational isomers (rotamers) of butane and 2-methylhexane will be examined using WebMO. This assignment is due March 4.

  Strain in cycloalkanes

  Angle and torsional strain in cycloalkanes will be calculated by comparing them to the corresponding open-chain alkanes. You may want to use these cyclohexane models rather than try to build chair and boat cyclohexane. This assignment is due March 14.

  Cationic intermediates in electrophilic aromatic substitution

  This assignment will be due on the same date (April 8) as the electrophilic aromatic substitution experiment.

  Aromaticity in heterocycles

  Using benzene for comparison, you will examine the aromaticity of a number of heterocyclic ring systems. For extra credit, you may want to look at the aromaticity of the nucleic acid bases cytosine and uracil. This project will be due by 8 AM on Wednesday, May 4.

  Lab Data; see the lab schedule

  Data from group experiments will be posted here as PDF or MS Office documents.

  Virtual Spectroscopy

  Individual assignment pages are posted here, by name:
  

  Cianci	Moore	Steele
  Thacker	Vimbiso

  Keto-enol equilibrium studies by NMR

  Raw integration numbers may be obtained from this Adobe Acrobat document. All students should use all the data here, a combination of the data collected by everyone.
  
  Assume that the enols of 2,4-pentanedione (acetylacetone), 1-phenyl-2,4-pentanedione (benzoylacetone) and ethyl 3-oxobutanoate (ethyl acetoacetate) have the structures shown below.

  

  Do your computational results support this assumption?

  Kinetics of the esterification of trifluoroacetic acid by NMR

  We will compare the rates of esterification of three of the four different C₄H₁₀O alcohols: 1-butanol, 2-butanol and 2-methyl-1-propanol.

  tert-Butyl alcohol reacts reversibly with trifluoroacetic acid, and so the rate constant is not trivial to obtain from NMR data.

  This file demonstrates how the data are obtained. The raw data are contained in this Excel spreadsheet. You will need to calculate the rate constants by taking the reciprocal of the experimental T1 values.
  
  You should account for differences in the rate constants in terms of structure. Be sure to explain whether you think the observed differences are significant. (Hint: statistical analysis will be needed to determine this.)

  Organic Qualitative Analysis

  Here is the student assignment list, which tells which unknowns are assigned to which student. Mass spectral data (and boiling points of liquids) are included.
  
  

  IR spectrum of Nujol

  Alkyl halide results

  2011 results are posted here (Excel spreadsheet). The report is due Friday, March 19.