1. GUIDED-INQUIRY PROJECTS AND EXPERIMENTS CHRISTINA NORING HAMMOND VASSAR COLLEGE POUGHKEEPSIE, NY

2. MONDAY LAB: Experiment 10 E2 ELIMINATION OF 2-BROMOHEPTANE:
INFLUENCE OF THE BASE
QUESTION: What effect does the bulkiness of the base have on the product
composition in the E2 debromination of 2-bromoheptane?
• Microscale procedure
• Students work in teams of two with one using each base.
• Product composition determined by GC analysis.

3. EXP. 8.1: RADICAL CHLORINATION REACTIONS
QUESTION: Do statistical factors determine the product composition in radical chlorination reactions or do electronic factors play a role?
• Green Chemistry: Cl2 is generated in situ from household bleach (5.25% NaOCl)
and 3 M HCl:
• Substrates used:
• Microscale experiment.
• Teamwork.
• Irradiation with 300-watt unfrosted incandescent bulb until the yellow color
of Cl2 disappears (~5 min).
• Product mixture analyzed by GC.

4. EXP 8.2: PHOTOBROMINATION OF 1,2-DIPHENYLETHANE
QUESTION: Which diastereomer forms in the photobromination of
1,2-diphenylethane?
• Green Chemistry: Bromine is generated in situ:
• Irradiation done with 100-watt incandescent bulb for ~10 min.
• Product analyzed by m.p.

5. PROJECT 6: E1/E2 ELIMINATION REACTIONS
QUESTION: Compare the mixture of isomeric alkenes produced by an acid-
catalyzed dehydration and a base-catalyzed dehydrochlorination.
Are the product ratios influenced primarily by product stability?
• Two-week project for a team of two students.

6. PROJECT 6: E1/E2 ELIMINATION REACTIONS
Project 6.1 Acid-Catalyzed Dehydration of 2-Methyl-2-butanol
QUESTION: Does product stability or do statistical factors determine the ratio
of 2-methyl-2-butene to 2-methyl-2-butene?
Project 6.2 Synthesis of 2-Chloro-2-methylbutane
PURPOSE: To synthesize 2-chloro-2-methylbutane for use in a
dehydrochlorination reaction.

7. PROJECT 6: E1/E2 ELIMINATION REACTIONS
Base-Catalyzed Dehydrochlorination of 2-Chloro-2-methylbutane
QUESTION: Does product stability or do statistical factors determine the ratio
of 2-methyl-2-butene to 2-methyl-2-butene?
• Both students run the reaction using product prepared in 6.2.

8. Project 4 INTERCONVERSION OF 4-tert-BUTYCYCLOHEXANOL
AND 4-tert-BUTYCYCLOHEXANONE
QUESTION: What is the stereoselectivity of NaBH4 reduction of
4-tert-butylcyclohexanone?
Project 4.1
Green Chemistry: Sodium Hypochlorite Oxidation of 4-tert-Butylcyclohexanol
• Rate of reaction dependent on rate of stirring.
• When is the reaction complete?
• Reaction monitored by TLC analysis using p-anisaldehyde visualization.

9. INTERCONVERSION OF 4-tert-BUTYCYCLOHEXANOL
AND 4-tert-BUTYCYCLOHEXANONE
Project 4.2
Sodium Borohydride Reduction of 4-tert-Butylcyclohexanone
• Reaction can be monitored by TLC.
• Product analysis by GC and/or NMR.
-trans isomer: axial proton on C with --OH at 3.5 ppm.
-cis isomer: equatorial proton at 4.03 ppm.

10. PROJECT 12: BIOCHEMICAL CATALYSIS AND
THE STEREOCHEMISTRYOF BOROHYDRIDE REDUCTION
QUESTION: What the stereoselectivity in the sodium borohydride reduction of
benzoin to 1,2-diphenyl-1,2-ethanediol?
PROJECT 12.1
• Green Chemistry: Traditional catalyst, KCN, is replaced with thiamine.
• Benzoin condensation is first step in a three-step project.

11. PROJECT 12: BIOCHEMICAL CATALYSIS AND
THE STEREOCHEMISTRYOF BOROHYDRIDE REDUCTION
PROJECT 12.2
• Cyclic acetal analyzed by NMR.

12. PROJECT 12: BIOCHEMICAL CATALYSIS AND
THE STEREOCHEMISTRYOF BOROHYDRIDE REDUCTION
• NMR analysis by chemical shifts of the -CH3 groups and the methine protons.

13. PROJECT 14: SUGARS: GLUCOSE PENTAACETATES
QUESTIONS: What is the relative stability of - and -D-glucose pentaacetate?
How can you distinguish between kinetic and equilibrium control
in the synthesis of the glucose pentaacetates?
PROJECT 14.1 Synthesis of - and -D-Glucose Pentaacetate

14. PROJECT 14: SUGARS: GLUCOSE PENTAACETATES
PROJECT Investigation of Kinetic and Equilibrium Control in the
Glucose Pentaacetate System
• PRELABORATORY ASSIGNMENT: Analyze NMR spectra of both crude
and recrystallized - and -D-glucose pentaacetates.
• C-1 (anomeric) protons: - glucose, 6.33 ppm; - glucose, 5.72 ppm.
• Determine ratio of - and -D-glucose pentaacetate in each sample.
• Are the recrystallized samples at least 95% pure?
• Design a set of experiments to investigate the equilibration of - and
-D-glucose pentaacetates.
• Students are given two isomerization methods to use for the tests.
• NMR analysis of all products.

15. PROJECT 14: SUGARS: GLUCOSE PENTAACETATES
PROJECT Computational Chemistry Experiment
• In aq. solutions of -glucose anomer, the C-1 hydroxyl group is equatorial
and with the-glucose anomer, the C-1 hydroxyl group is axial.
• Build models of axial- and equatorial-isomers of:
• Calculate heats of formation for each isomer.
• Use difference in heats of formation for the 2-acetoxytetrapyran conformers
to calculate Keq for - and -D-glucose pentaacetate.
• Are your calculations consistent with your investigations of kinetic and
equilibrium control in the glucose pentaacetate system?

16. ACKNOWLEDGEMENTS • Paul F. Schatz, University of Wisconsin
• Colleagues and students at Vassar and Carleton
• Jhong Kim, UC Irvine
• My many Vassar student assistants
• W. H. Freeman and Co, publishers

19. PROJECT 9: BROMINATION OF
CYCLOHEX-4-ENE-cis-1,2-DICARBOXYLIC ACID
QUESTION: What is the stereochemistry of bromine addition to the double bond?
• A three-step synthesis project.
• First step: Diels-Alder synthesis and subsequent hydrolysis of anhydride.
• Pyridinium tribromide is the source of Br2.
• Dimethyl ester is subsequently prepared and stereochemistry determined by NMR.

20. PROJECT 9: BROMINATION OF CYCLOHEX-4-ENE-cis-1,2-DICARBOXYLIC ACID
anti Addition of Bromine: Bromonium ion pathway.
syn Addition of Bromine: Carbocation pathway.

21. TUESDAY LAB GREEN CHEMISTRY: SYNTHESIS AND HYROGENATION
OF SUBSTITUTED CHALCONES A GUIDED-INQUIRY PROJECT
QUESTION: Which functional groups are reduced in the hydrogenation
of a polyfunctional molecule?
Part 1
Synthesis of the Chalcone
• Use concentrated aqueous NaOH solution for reaction.
• Product recrystallized from 95% ethanol.
• Product analyzed by IR and NMR.
Reference: Palleros, D. R. J. Chem. Educ. 2004, 81, 1345–1347.

22. GREEN CHEMISTRY: SYNTHESIS AND HYROGENATION
OF SUBSTITUTED CHALCONES A GUIDED-INQUIRY PROJECT
Part 2
Hydrogenation of the Chalcone
• Determine a suitable TLC solvent for the chalcone.
• Completion of reaction determined by TLC analysis.
• Product analyzed by TLC, IR, NMR, and GC-MS.